Friday, December 27, 2013
Video IF circuit TV
The main function of the video IF is to change the 38.0 MHz IF signal into the CVBS signal which later fed into the sound and video to the chroma.
VIF section consists of a series as follows:
IF amplifier
This section serves to strengthen the signal until the signal level is required. IF amplifier is equipped with AGC (Automatic Gain Controller) which controls the strengthening of the IF amplifier so that a constant amplitude output video. Amplifier frequency range from 32 ~ 60 MHz makes this amplifier suitable for applications multistandar.
PLL demodulator and VCO (voltage control oscillator)
IF signal is separated with the help of PLL detector. PLL detector produces a phase reference signal with the IF signal carrier and about 60 KHz bandwidth is determined by PLL loopfilter pin 37. Obtained by comparing the frequency demodulation reference signal with the incoming IF signal. Are required reference frequency (38.0 MHz) generated by the VCO. Appropriate VCO frequency is determined by system calibration using the crystal as a reference. PLL can detect the IF frequency up to ± 1 MHz based on FPLL (Frequency Phase Lock Loop System) which will provide an output signal to the PLL loopfilter for the difference frequency is obtained. If the phase IF signal with a reference signal, the signal is transmitted to the demodulator. Demodulator to control the positive and negative modulation, the selection made by the IIC bus. Low pass filter after the output signal demodulator eliminates the demodulation is not required to process the video.
Video Buffer
Video buffer to produce a video output with an amplitude of the right and keep the video output from the noise peak occurring. The bandwidth of the video buffer at least 6 MHz. In the video there are White spot clamp buffer (for positive modulation) and the noise inverter Clamp (for negative modulation) which keeps the amplitude of the video does not exceed the typical price.
Thursday, December 26, 2013
A 4 Digit Keypad Controller Switch Circuit
A 4-Digit Keypad Controller Switch CircuitThis is a universal version of the Four-Digit Alarm Keypad . I have modified the design to free up the relay contacts. This allows the circuit to operate as a general-purpose switch. It also means that it can be used to control all of my Alarm Circuits. Ive used a SPCO/SPDT relay - but you can use a multi-pole relay if you wish.
The relay is energized by pressing a single key. Choose the key you want to use - and connect it to terminal "E". Choose the four keys you want to use to de-energize the relay - and connect them to "A B C & D". Wire the common to R1 and all the remaining keys to "F".
The Circuit is easy to use. When you press "E" - current through D2 & R9 turns Q6 on - and energizes the relay. The two transistors - Q5 & Q6 - form a "Complementary Latch". So - when you release the key - the relay will remain energized.
To de-energize the relay - you need to press keys "A B C & D" in the right order. When you do so - pin 10 of the IC goes high - and it turns Q4 on through R8. Q4 connects the base of Q6 to ground. This unlatches the complementary pair - and the relay drops out.
Any keys not wired to "A B C D & E" are connected to the base of Q3 by R7. Whenever one of these "Wrong" keys is pressed - Q3 takes pin 1 low and the code entry sequence fails. If "C" or "D" is pressed out of sequence - Q1 or Q2 will also take pin 1 low - with the same result. If you make a mistake while entering the code - simply start again.
The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 or 8 terminals will NOT do. With a 12-key pad - over 10 000 different codes are available. If you need a more secure code - use a bigger keypad with more "Wrong" keys wired to "F". A 16-key pad gives over 40 000 different codes.
The relay is energized by pressing a single key. Choose the key you want to use - and connect it to terminal "E". Choose the four keys you want to use to de-energize the relay - and connect them to "A B C & D". Wire the common to R1 and all the remaining keys to "F".
The Circuit is easy to use. When you press "E" - current through D2 & R9 turns Q6 on - and energizes the relay. The two transistors - Q5 & Q6 - form a "Complementary Latch". So - when you release the key - the relay will remain energized.
To de-energize the relay - you need to press keys "A B C & D" in the right order. When you do so - pin 10 of the IC goes high - and it turns Q4 on through R8. Q4 connects the base of Q6 to ground. This unlatches the complementary pair - and the relay drops out.
Any keys not wired to "A B C D & E" are connected to the base of Q3 by R7. Whenever one of these "Wrong" keys is pressed - Q3 takes pin 1 low and the code entry sequence fails. If "C" or "D" is pressed out of sequence - Q1 or Q2 will also take pin 1 low - with the same result. If you make a mistake while entering the code - simply start again.
The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 or 8 terminals will NOT do. With a 12-key pad - over 10 000 different codes are available. If you need a more secure code - use a bigger keypad with more "Wrong" keys wired to "F". A 16-key pad gives over 40 000 different codes.
Wednesday, December 25, 2013
Battery Charger with Temeperature Sensor
Battery with a LM35 temperature sensor on the charger used to monitor the battery temperature is in charge. Battery temperature sensor is needed because the battery temperature will rise at the time in charge. Battery temperature sensor LM35 temperature sensor has high accuracy in monitoring the battery temperature, it is because the temperature sensor LM35 is a temperature sensor that can convert temperature changes into voltage changes linearly.
At the time of the charge a battery will experience changes in temperature, where the battery temperature will begin to rise when the battery began to fill. To avoid over heat the battery, the battery temperature sensor LM35 temperature sensor is required to terminate the battery charging current to avoid overheating.
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| Battery charger with temperature sensor schematic |
On the battery charger circuit temperature sensor with temperature sensor 35 lm above the R1 is used for setting the maximum value of the desired temperature. Therefore, when the temperature was in-charge the battery begins to rise and reach temperatures setup then this series will break the current battery charge.
Tuesday, December 24, 2013
Class B audio amplifier based on TDA1553
Here is the circuit of a Class B audio amplifier based on TDA1553. TDA1553 is a monolithic audio amplifier class B, containing 2 x 22 watt amplifier in bridge configuration load attached. The amplifier operates from 12V DC and develops intentionaly for car audio applications. The IC also has a lot of good features such as short circuit protection, protection of the load dump, reverse polarity protection, speaker protection, etc.
In the circuit, C5 and C4 are decoupling capacitors C3 input, while setting the delay for speaker protection. C1 and C2 are filter capacitors of the offer.
Notes :
- Assemble the circuit on a good quality PCB.
- Use 12V DC for powering the circuit.
- The circuit can deliver 22W per channel into 4 ohm speakers.
- Fit the IC with a proper heat sink.
Monday, December 23, 2013
Understanding Audio Amplifiers
Audio amplifiers are by the side of the very spirit of each at your house plays practice. to the same degree the quality and output power rations of at presents loudspeakers multiply, so puzzle out the stress of audio amps. It is fast to pick an amplifier known the obese come to of models and designs. I bidding explain more or less of the nearly everyone customary amplifier designs such so "tube amps", "linear amps", "division-AB" and "class-D" as well as "class-T amps" to help you understand some of the provisos commonly used by amplifier manufacturers. This conductor ought to and help you symbol not permitted which topology is ideal intended for your specific attention.
Simply set, the intent of an audio amplifier is to convert a low-power audio imply into a soaring-power audio signal. The high-power signal is huge an adequate amount to drive a loudspeaker amply loud. wearing order to solve to, an amp uses single before additional elements which are controlled by the low-power suggest to generate a large-power signal. These elements range from tubes, bipolar transistors to FET transistors.
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| Audio Power Amplifier |
Tube amplifiers used to occur everyday a little decades before. A tube is able to control the current stream according to a control voltage which is connected to the tube. Unfortunately, tube amplifiers state a somewhat towering amount of distortion. Technically speaking, tube amplifiers motivation introduce elevated harmonics into the sign. However, this characteristic of tube amps still makes these standard. Many nation explain tube amps for instance having a kindhearted sound versus the cold sound of solid state amps.
an added drawback of tube amps, though, is the low power efficiency. The majority of power which tube amps consume is being degenerate as leg and lone a portion is being converted into audio power. additionally, tubes are quite expensive to get on to. like this tube amps experience mostly been replaced by solid-state amps which I motivation look on then.
Solid state amps reinstate the tube with semiconductor elements, typically bipolar transistors or else FETs. The most primitive type of solid-state amps is famous to the same degree category-A amps. modish class-A amps a transistor controls the current arise according to a lesser-level show. various amps avail yourself of a pointer machinery in order to underestimate the choral distortion. Class-A amps produce the lowest distortion and regularly furthermore the lowest amount of clatter of one amplifier architecture. If you need ultra-low distortion afterward you be supposed to take a closer look by panache-A models. The chief drawback is with the purpose of like to tube amps class A amps have very low efficiency. like a upshot these amps require corpulent heat up sinks to dissipate the shrunken energy and are typically rather bulky.
Class-AB amps pick up on the efficiency of class-A amps. They use a string of transistors to break up the large-level signals into two separate areas, every one of which can remain greater than before further efficiently. when such, style-AB amps are regularly less important than class-A amps. However, this topology adds selected non-linearity before distortion appearing in the region wherever the sign switches involving individuals areas. As such class-AB amps typically tolerate top distortion than class-A amps.
Class-D amps upgrade on the efficiency of rank-AB amps even advance by using a switching transistor which is constantly being switched on before inedible. thus this switching stage hardly dissipates a few power and along these lines the power efficiency of class-D amps commonly exceeds 90%. The switching transistor is being controlled by a pulse-width modulator. The switched overweight-level gesticulate has to happen lowpass filtered in the field of order to remove the switching signal and recover the audio signal. Due to non-linearities of the pulse-width modulator and the switching transistor itself, categorize-D amps by nature be inflicted with amongst the highest audio distortion of every audio amplifier.
To solve the question of exalted audio distortion, newer switching amplifier designs incorporate response. The better indication is compared with the real McCoy low-level signal and errors are corrected. A well-recognized architecture which uses this type of pointer is known being "course group-T". Class-T amps before "t amps" do audio distortion which compares with the audio distortion of class-A amps while by the side of the same type offer the power efficiency of class-D amps. along these lines t amps can remain made tremendously undersized and still complete elevated audio fidelity.
Sunday, December 22, 2013
Car Battery Charger 12Volt Circuit Diagram
Car Battery Charger 12Volt Circuit DiagramThe aloft circuit claimed accept adeptness to anticipate array blackmail that accomplish electrolyte absent due to evaporation. This ambit will annihilate the problems by ecology the battery’s action of allegation through its attendant ascendancy ambit by applying a aerial allegation accepted until the array is absolutely charged. Back charging is complete, it turns on the red LED (LD2) and deactivates the charging circuit.
This ambit is fatigued to allegation 12V batteries ONLY. Certain accent should be taken back base up this circuit. They are the access of the agent to the ambit board, and those bartering accepted to the array actuality charged. These access should be fabricated with cables accepting a ample cross-sectional breadth to anticipate voltage-drop and calefaction accession back accepted flows through them.
Saturday, December 21, 2013
TDA2003 Car amplifier
This is a very popular series of amplifiers audio users who require maximum aduio results and of course with a relatively cheap price. This circuit requires a minimum voltage and maximum 9 Volt and 30 Volt. This amplifier circuit using ic TDA2003, which is used in car audio power, because of making these amplifiers can easily be made on each speaker of the amplifier. By using ic and component quality is very good circuit used separately. The circuit can be seen below.
Technical information:
Supply voltage = 12V
Output = 10W
Friday, December 20, 2013
13 Color LED Rainbow Schematic
Only a few years ago, the choice of LEDs was limited to IR, red, yellow, and green. The LED manufacturers have been busy extending the spectrum, and filling in the gaps. The latest generation of organic LEDs (OLEDs) has added some dazzling new colors to the spectrum. This circuit uses a set of 13 differently colored LEDs to generate a full color spectrum. The photo does not fully represent the colors generated due to camera limitations. The real-world display is very eye-catching. If you want to "trick out" your PC, this circuit is for you. Forget about those boring blue PC light displays.
13 Color LED Rainbow Circuit Diagram:
Specs:
The LM2940T-5.0 low dropout voltage regulator converts the 6-12V DC input power to regulated 5 Volts. It was chosen over a standard 7805 regulator so that the circuit could maintain regulation while operating on a 6V battery. The 1N4001 diode protects the circuit from reverse polarity, if a battery or power supply capable of generating over 1 amp is used, a 1 amp fuse should be installed between the supply and the circuit. The 5 Volts is used to drive each of the LEDs through individual current limiting resistors.
The resistor values were determined experimentally for equal brightness. Values are given as examples only, different sources of LEDs will require different resistor values. Resistor selection turns out to be the most difficult part of the circuits construction. A 100 ohm resistor in series with a 1K pot could be used in place of each resistor if individual brightness adjustments are desired. The table below lists the LED colors and wavelengths.
LED Color Wavelength Description
Deep Red 700nm ---------
Red 660nm traditional red
Orange Red 635nm "high efficiency" red
Orange 623nm also called red orange
Amber 594nm ---------
Yellow 588nm & traditional yellow
Yellow Green 567nm traditional green
True Green 523mn --------
Cyan 501nm verde green, blue green
Aqua 495?nm ---------
Deep Blue 470nm ultra blue
Powder Blue 430nm first generation "powder blue"
Violet 410nm ---------
Construction:
The circuit was built on a prototype perforated board with printed solder pads. The circuitry is hand-wired on the back side of the board. Care should be taken when soldering to the LEDs, a clip-on heat sink should be used while soldering the leads. Care should be taken to avoid zapping the LEDs on the violet side of the spectrum, they are sensitive to static electricity. The circuit board can be mounted on a piece of white hardboard, the white paint reflects the colors nicely.
Use:
Apply power to the circuit and enjoy the colorful glow. Do not stare directly into the array at close range for extended periods, some of the LEDs are extremely bright.
Taking The Circuit Further:
The spectrum could be extended on both the IR and UV sides. A brief scan through the Mouser catalog indicates the availability of these IR wavelengths: 940nm 880nm, 875nm, 870nm, 850nm. UV LEDs at 400nm, 395nm and 380nm are also available. There are also many LED colors available with wavelengths between the 13 colors shown, the colors selected were chosen for an evenly spaced color spectrum.
An open-collector LED driver circuit could be connected to the negative LED leads for computer control.The circuit could be used in conjunction with a photo detector for characterizing optical filter curves. Typically, the photo detector output is sent to a logarithmic converter, the log-ratio of the direct light versus the filtered light characterizes the attenuation at a given wavelength.
Parts:
Most of the LEDs were purchased from Digi-Key, Jameco, and Mouser. All of the parts were T1-3/4 size, clear packages were used wherever possible. LEDs from different manufacturers may have different focus characteristics. All of the resistors are 1/4 Watt parts. LED part numbers are not available, the rainbow was assembled from parts that were accumulated over several years. Beware that different LED manufacturers use different names for their colors, the wavelength is the best indicator of the color. The Aqua LED is the most difficult part to find, All Electronics carries them, although the wavelength is unspecified.
13 Color LED Rainbow Circuit Diagram:
Specs:
- Operating Voltage: 6-12V DC
- Operating Current: 145ma at 12V DC
The LM2940T-5.0 low dropout voltage regulator converts the 6-12V DC input power to regulated 5 Volts. It was chosen over a standard 7805 regulator so that the circuit could maintain regulation while operating on a 6V battery. The 1N4001 diode protects the circuit from reverse polarity, if a battery or power supply capable of generating over 1 amp is used, a 1 amp fuse should be installed between the supply and the circuit. The 5 Volts is used to drive each of the LEDs through individual current limiting resistors.
The resistor values were determined experimentally for equal brightness. Values are given as examples only, different sources of LEDs will require different resistor values. Resistor selection turns out to be the most difficult part of the circuits construction. A 100 ohm resistor in series with a 1K pot could be used in place of each resistor if individual brightness adjustments are desired. The table below lists the LED colors and wavelengths.
LED Color Wavelength Description
Deep Red 700nm ---------
Red 660nm traditional red
Orange Red 635nm "high efficiency" red
Orange 623nm also called red orange
Amber 594nm ---------
Yellow 588nm & traditional yellow
Yellow Green 567nm traditional green
True Green 523mn --------
Cyan 501nm verde green, blue green
Aqua 495?nm ---------
Deep Blue 470nm ultra blue
Powder Blue 430nm first generation "powder blue"
Violet 410nm ---------
Construction:
The circuit was built on a prototype perforated board with printed solder pads. The circuitry is hand-wired on the back side of the board. Care should be taken when soldering to the LEDs, a clip-on heat sink should be used while soldering the leads. Care should be taken to avoid zapping the LEDs on the violet side of the spectrum, they are sensitive to static electricity. The circuit board can be mounted on a piece of white hardboard, the white paint reflects the colors nicely.
Use:
Apply power to the circuit and enjoy the colorful glow. Do not stare directly into the array at close range for extended periods, some of the LEDs are extremely bright.
Taking The Circuit Further:
The spectrum could be extended on both the IR and UV sides. A brief scan through the Mouser catalog indicates the availability of these IR wavelengths: 940nm 880nm, 875nm, 870nm, 850nm. UV LEDs at 400nm, 395nm and 380nm are also available. There are also many LED colors available with wavelengths between the 13 colors shown, the colors selected were chosen for an evenly spaced color spectrum.
An open-collector LED driver circuit could be connected to the negative LED leads for computer control.The circuit could be used in conjunction with a photo detector for characterizing optical filter curves. Typically, the photo detector output is sent to a logarithmic converter, the log-ratio of the direct light versus the filtered light characterizes the attenuation at a given wavelength.
Parts:
Most of the LEDs were purchased from Digi-Key, Jameco, and Mouser. All of the parts were T1-3/4 size, clear packages were used wherever possible. LEDs from different manufacturers may have different focus characteristics. All of the resistors are 1/4 Watt parts. LED part numbers are not available, the rainbow was assembled from parts that were accumulated over several years. Beware that different LED manufacturers use different names for their colors, the wavelength is the best indicator of the color. The Aqua LED is the most difficult part to find, All Electronics carries them, although the wavelength is unspecified.
Thursday, December 19, 2013
Simple Light Alarm Schematic
A very simple light alarm schematic circuit project can be designed using some common electronic parts, as you can see in the circuit diagram bellow . This light alarm schematic circuit project will sound as soon as the drawer is opened and light falls on the Darlington phototransistor. The output alarm may be redesigned to activate a relay or triac. This simple light alarm schematic circuit project use a MAL12 LDR photoresistor as a sensor .
Light Alarm Schematic Circuit diagram
The 14011 quad , 2 input, NAND gate is wired up to oscillate when the input to it goes high, that is the BC557 transistor turns on after light is detected by the MAL12. The oscillating output from the 14011 turns the BC547 on and off , making the buzzer to sound. After the alarm has started and it is put back into dark conditions , alarm will continue to sound for about 3 - 5 seconds. This is due to the 1uF capacitor and 4M7 resistor which keep the input to the 14011 high .
The circuit is very simple and must be powered from a simple 9 volts DC power supply or a 9 volt battery .
Light Alarm Schematic Circuit diagram
The circuit is very simple and must be powered from a simple 9 volts DC power supply or a 9 volt battery .
Wednesday, December 18, 2013
20 Watt Power Amplifier Using Lm1875
The LM1875 is a monolithic power amplifier offering very low distortion and high quality performance for consumer audio applications. The LM1875 delivers 20 watts into a 4Ω or 8Ω load on ±25V supplies. Using an 8 load and ±30V supplies, over 30 watts of power may be delivered. The amplifier is designed to operate with a minimum of external components. Device overload protection consists of both internal current limit and thermal shutdown.
20 Watt Power Amplifier Circuit Diagram
The LM1875 design takes advantage of advanced circuit techniques and processing to achieve extremely low distortion levels even at high output power levels. Other outstanding features include high gain, fast slew rate and a wide power bandwidth, large output voltage swing, high current capability, and a very wide supply range. The amplifier is internally compensated and stable for gains of 10 or greater.
Features:
• Up to 30 watts output power
• AVO typically 90 dB
• Low distortion: 0.015%, 1 kHz, 20 W
• Wide power bandwidth: 70 kHz
• Protection for AC and DC short circuits to ground
• Thermal protection with parole circuit
• High current capability: 4A
• Wide supply range 16V-60V
• Internal output protection diodes
• 94 dB ripple rejection
• Plastic power package TO-220
20 Watt Power Amplifier Circuit Diagram
Features:
• Up to 30 watts output power
• AVO typically 90 dB
• Low distortion: 0.015%, 1 kHz, 20 W
• Wide power bandwidth: 70 kHz
• Protection for AC and DC short circuits to ground
• Thermal protection with parole circuit
• High current capability: 4A
• Wide supply range 16V-60V
• Internal output protection diodes
• 94 dB ripple rejection
• Plastic power package TO-220
Tuesday, December 17, 2013
50MW Audio Amplifier circuit
50MW Audio Amplifier circuitDue to recent increases in bias voltage between the emitter and base decreases as a result of minimizing driving. Input impedance is 500 ohms and the voltage gain is approximately five to eight ohm speaker connected. The voltage swing around the speaker is 2 volts without distorting production and capacity is at the same time in the 50 milliwatt range. A high voltage provided as well as the addition of heat sinks in the output transistors would be a great source of more power. Circuit thirty milliamperes draw a supply of 9 volts.
Monday, December 16, 2013
TV Vertical Protectors
Vertical Protectors (another term surge protector or Vertical CRT Neck Guard or protector) . If the vertical deflection does not work, then the raster will glow a horizontal line. This can cause the picture tube phosphor layer was destroyed by fire when the aircraft be kept alive in the long term.
The workings of the system-vertical surge protector that can be found there are several kinds:
Continue[...]
There are several types of system protectors, vertical relationships:
- Protector surge protector is connected with x-ray to the horizontal which will trigger the horizontal oscillator is not working
- Protectors gets connected to microcontrol that will trigger the "power off" so that the plane will turn off automatically or plane alive but raster becomes dark (brightnes level down).
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| Vertical Protect |
- Using sampling pulses from vertical-out IC which is connected to microcontrol . If microcontrol not receive these pulses the surge protector will work.
- Using a sampling of the voltage supply Vcc-vertical IC connected to the IC microcontrol using a diode. In the normal kondidi no voltage on the pin-IC microcontrol protection. If the supply voltage Vcc or a short break then the voltage on the pin- microcontrol protection will come short to ground through the diode and trigger protection to actively work
- Using the IC supply current sampling vertical-out that will actively work if the current exceeds supply. As the sensor protector installed here a series resistor and a transistor in the supply line where it works similar to the OCP.
Problems or possibilities that may cause the protector of vertically-active work:
- Vertical IC-out short (broken)
- No voltage supply to the vertical IC-out.
- Vertical lines of the IC pulse-out to any part microcontrol broken or damaged
- Vertical deflection section does not work (damage to the IC)
Sunday, December 15, 2013
Low Power Transceiver Using by ADF7242
This low power transceiver circuit project is designed using the ADF7242 fully integrated low-cost, short-range, low power transceiver designed for operation in the global 2.4 GHz ISM band.The receive path of the ADF7242 low power transceiver circuit is based on a zero-IF architecture enabling high blocking and selectivity performance. The transmit path is based on a direct closed loop VCO modulation scheme. The ADF7242 has a low consumption power that make it suitable for battery powered systems.
Low Power Transceiver Circuit diagram
The ADF7242 supports IEEE 802.15.4 compliant DSSS-OQPSK modulation with a bitrate of 250 kbps and also supports FSK and GFSK modulation with bitrates from 62.5 kbps to 2 Mbps.ADF7242 fully supports arbitrary data rates only for FSK mode of operation. The ADF7242 also has a built in battery monitor features that has a very low power consumption and may be used in parallel with any mode of operation, except SLEEP state. The battery monitor generates a battery alert interrupt for the MCU when the battery voltage drops below the programmed threshold voltage.
Low Power Transceiver Circuit diagram
The ADF7242 supports IEEE 802.15.4 compliant DSSS-OQPSK modulation with a bitrate of 250 kbps and also supports FSK and GFSK modulation with bitrates from 62.5 kbps to 2 Mbps.ADF7242 fully supports arbitrary data rates only for FSK mode of operation. The ADF7242 also has a built in battery monitor features that has a very low power consumption and may be used in parallel with any mode of operation, except SLEEP state. The battery monitor generates a battery alert interrupt for the MCU when the battery voltage drops below the programmed threshold voltage.
Saturday, December 14, 2013
Amplifier for Paralelling Headphone
The circuit is useful to strengthen the voice on the headphones, which is where the headphones have a stereo output is used and paralleled to some headphones. The circuit is based on the TDA2822 amplifier circuit modified to ampifier headphones.
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Amplifier for Paralelling Headphone |
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| Paralel Headphone Wiring Diagram |
Friday, December 13, 2013
2 4GHz WiFi ISM Band Scanner Firmware and Sowtware Part 2
2.4GHz WiFi & ISM Band Scanner. Description and Schematic Part 1
PIC Firmware
The firmware running on the PIC18F2550 was written for the CCS C compiler and uses the CCS USB protocol stack, which in turn appears to be derived from Microchip code. At the top level it is quite simple, it just repeatedly steps through the frequency range taking readings.
For each frequency it takes repeated readings until it gets what seems to be a consistent value. It then saves that value and moves on to the next frequency. When it has finished running through the band it sends off all readings to the computer over the USB. The CYWUSB6935 chip steps 1MHz at a time and the band is 85MHz wide, so the number of readings sent to the computer is 85. Despite the repeated measurements needed to get a consistent reading the chip achieves quite a good performance, about 4 complete spectrum scans every second.
The firmware and source code for the 18F2550 is available from the download section below.
Windows Software
The software running on the computer was written in Visual Basic 5. It is not particularly sophisticated, for example it keeps polling the USB interface to see if new data has arrived and that uses up a lot of CPU time. But, you dont generally use the scanner for a lot of time and you would not normally be running computer games at the same time, so this inefficiency is not of great importance.
The software on the computer saves the set of readings into an array. When it comes to drawing the spectrum display on the screen it steps through all the saved readings for each frequency looking for the highest reading, and it is that highest reading that it draws on the screen for that frequency. As a new reading is received the oldest reading in the array is discarded. The slider on the screen controls how many readings are saved for each frequency, the default is 350 readings which represents about 90 seconds of data.
All this means that the delay has a "memory" and one high reading will hang around for 90 seconds until it is flushed out. This is done because devices normally hop around in frequency and it would be hard to see what frequencies were popular unless there was some way of holding on to the reading for a while. You can see this in action when there is a noise spike. That spike would remain on the screen for (say) 90 seconds then disappear. But a device that communicated on that frequency (amongst others) would in most probability revisit that frequency within the 90 second period and that would place a new high value into the array of values for that frequency.
By adjusting the slider you control the size of this array and consequently the amount of time that it would take to flush a reading out. Smaller numbers flush more quickly, larger ones take more time. You can pause the display by clicking on the Pause button. Clicking on it again will clear the array and start a new collection. This is also a handy way of clearing everything to restart with a fresh display.
The Export button will export the current set of readings to a .csv file which can be loaded into a spreadsheet like Excel.
As usual, the software and source code is available for download below.
C# Version of the Software
A reader, Jim McCullers in the USA, took up the challenge of porting the desktop software to a more modern environment. The code he wrote compiles under Microsoft Visual C# 2010 Express (the free version) and is also available for download below.
He did not make any major changes to the structure or look but created a new version of the MPUSBAPI to suit C# and made it into a class. The mpusbapi.dll module must be in the same directory folder as the executable so you will notice that he has copies in both the debug and release folders.
Plugging It In
Because the scanner uses standard USB it can be connected to any computer, although the software is written only for Windows XP, Vista and Windows 7.
Before you plug the scanner in you must install the software first. This is available in the download section below. Failure to install the software first will result in Windows identifying the scanner as an "Unidentified Device".
During installation of the software a device driver is installed and it is this that helps Windows identify the scanner. After you have correctly installed the software and plugged in the scanner you should see the device show up under "Other Devices" in Device Manager as shown on the left.
When you fire up the desktop software (ISMScanner.exe) you should see the message in the software window stating "Connected to Geoffs 2.4GHz Scanner". If you get "Scanner not found" then the scanner is not plugged in or not working.
The firmware running on the PIC18F2550 was written for the CCS C compiler and uses the CCS USB protocol stack, which in turn appears to be derived from Microchip code. At the top level it is quite simple, it just repeatedly steps through the frequency range taking readings.
For each frequency it takes repeated readings until it gets what seems to be a consistent value. It then saves that value and moves on to the next frequency. When it has finished running through the band it sends off all readings to the computer over the USB. The CYWUSB6935 chip steps 1MHz at a time and the band is 85MHz wide, so the number of readings sent to the computer is 85. Despite the repeated measurements needed to get a consistent reading the chip achieves quite a good performance, about 4 complete spectrum scans every second.
The firmware and source code for the 18F2550 is available from the download section below.
Windows Software
The software running on the computer was written in Visual Basic 5. It is not particularly sophisticated, for example it keeps polling the USB interface to see if new data has arrived and that uses up a lot of CPU time. But, you dont generally use the scanner for a lot of time and you would not normally be running computer games at the same time, so this inefficiency is not of great importance.
The software on the computer saves the set of readings into an array. When it comes to drawing the spectrum display on the screen it steps through all the saved readings for each frequency looking for the highest reading, and it is that highest reading that it draws on the screen for that frequency. As a new reading is received the oldest reading in the array is discarded. The slider on the screen controls how many readings are saved for each frequency, the default is 350 readings which represents about 90 seconds of data.
All this means that the delay has a "memory" and one high reading will hang around for 90 seconds until it is flushed out. This is done because devices normally hop around in frequency and it would be hard to see what frequencies were popular unless there was some way of holding on to the reading for a while. You can see this in action when there is a noise spike. That spike would remain on the screen for (say) 90 seconds then disappear. But a device that communicated on that frequency (amongst others) would in most probability revisit that frequency within the 90 second period and that would place a new high value into the array of values for that frequency.
By adjusting the slider you control the size of this array and consequently the amount of time that it would take to flush a reading out. Smaller numbers flush more quickly, larger ones take more time. You can pause the display by clicking on the Pause button. Clicking on it again will clear the array and start a new collection. This is also a handy way of clearing everything to restart with a fresh display.
The Export button will export the current set of readings to a .csv file which can be loaded into a spreadsheet like Excel.
As usual, the software and source code is available for download below.
C# Version of the Software
A reader, Jim McCullers in the USA, took up the challenge of porting the desktop software to a more modern environment. The code he wrote compiles under Microsoft Visual C# 2010 Express (the free version) and is also available for download below.
He did not make any major changes to the structure or look but created a new version of the MPUSBAPI to suit C# and made it into a class. The mpusbapi.dll module must be in the same directory folder as the executable so you will notice that he has copies in both the debug and release folders.
Plugging It In
Because the scanner uses standard USB it can be connected to any computer, although the software is written only for Windows XP, Vista and Windows 7.
Before you plug the scanner in you must install the software first. This is available in the download section below. Failure to install the software first will result in Windows identifying the scanner as an "Unidentified Device".
During installation of the software a device driver is installed and it is this that helps Windows identify the scanner. After you have correctly installed the software and plugged in the scanner you should see the device show up under "Other Devices" in Device Manager as shown on the left.
When you fire up the desktop software (ISMScanner.exe) you should see the message in the software window stating "Connected to Geoffs 2.4GHz Scanner". If you get "Scanner not found" then the scanner is not plugged in or not working.
Downloads
Firmware - HEX programming file v1.0, Firmware - source code v1.0 - download
Windows software v1.0 Installation (Visual Basic Version), Windows software v1.0 Source code (C# Version), Windows software v1.0 Source code (Visual Basic Version), Windows driver for Vista and Win 7 32/64 bit systems - download
Thursday, December 12, 2013
Thermopile Sensors LMP91050
Thermopile Sensors seeing that typically used trendy NDIR applications
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The LMP91050 is a programmable integrated Sensor Analog Front side (AFE) optimized on behalf of thermopile sensors, as typically used in NDIR applications. It provides a complete sign path solution amid a sensor and microcontroller to generates an output voltage proportional to the thermopile voltage. The LMP91050s programmability enables it to support multiple thermopile sensors with a single design because different to the multiple discrete solutions.
- Programmable gain amplifier
- “Dark indication” offset cancellation
- ropes outdoor filtering
- collective mode generator and 8 morsel DAC
- Ideal pro NDIR Sensing, Demand control ventilation, Automotive CO2 hut control, Alcohol detection
datasheet download : LMP91050
source
source
Wednesday, December 11, 2013
How to choose the best for your home theater system
Watching movies is a neat escape from the stressful lifestyle we live in. Watching movies in a wide screen and surround sound take you far away and into the movie scene you are watching. You watch it as if you were there in the movie scene. Of late, we can only experience this escape in a cinema. However, modern technology may be able to provide this same sight and sound experience right in your own living room. We will discuss the basic components of a home theater system in this article. Read on to understand how these basic components can deliver the best cinematic experience to a home theater system.
Home theater experts state that the most important consideration in setting up a home theater system is the size of the room where you will set up the home theater system. The most important component of the home theater system, which is the television, is dependent on the size of the room. Although, the recommendation is 27 inches television set at a minimum is necessary for your home theater set up. It is also a recommendation that a flat television is good for a home theater system because it exhibits fewer glares and produces a crisper image. Another major component of a home theater system that depends on the size of the room is the speaker. The number of speakers for your home theater system is dependent on the size of the room. You may add up to six speakers from the basic three speakers if you want a more lifelike sound. Adding a subwoofer may also be good to achieve a complete surround sound like in the movie theaters. Three speakers should be the minimum; you may go up to six if the room is big.
Another major for your home theater system is the DVD player. It is a recommendation that DVD players with progressive scan will be the best choice. This is because progressive scan produces sharp and flicker-free pictures. This however points back to the choice of television unit; you may need to check if the flat television set supports progressive scan signals. You may also acquire a five-disk carrousel DVD player. This will avoid having to stand up from your seat to change discs every so often. A minor consideration is the power rating that will determine how loud your speaker can be. Of course, almost all these depend on the size of the room to where the home theater system is going to be set up. Small room requires from few types of equipment, bigger rooms may require more and adding home theater furniture to your home theater system may be best. A bigger room thus requires more investments. A smaller room might require fewer but of good quality equipments to avoid the too basic feel of the home theater system.
Finally, you may acquire a beautifully designed home theater system if you consider hiring a home theater expert. If you can afford this, it will be best for you because the home theater expert will be able to effectively design and set up your home theater system. Your home theater designer may also add some features like home theater seating and other home theater furniture to be able to give the complete home theater package that closely resembles a real movie theater. Having the finest and high-quality home theater system will give you the most sought after set up that you could flaunt and enjoy to the max.
Tuesday, December 10, 2013
Wideband Two Pole High Pass Filter Schematic
The circuit provides a 10MHz cutoff frequency. Resistor R3 ensures that the input capacitance of the amplifier does not interact with the filter response at the frequency of interest. An equivalent low pass filter is similarly obtained by capacitance and resistance transformation.
Wideband Two-Pole High-Pass Filter Schematic
Wideband Two-Pole High-Pass Filter Schematic
Monday, December 9, 2013
Battery charger circuit
This cahrger based on chargeing voltage 2,4 Volts per cell , in accordance with most manufacterers recomendation. This circuit pulses the battery under with 14.4 Volts ( 6 cells x 2,4 volts per cell) at a rate 120 Hz.
Sunday, December 8, 2013
12V battery indicator level
The following sequence is useful to show the battery voltage (battery) 12 volts. Voltage level is shown with four lights led. To facilitate the reading of the led is arranged in a vertical array. Led top three chosen by the green LED while the lowest is selected the color red. If the battery voltage continues to decline (because of usage), the Led-Led will turn off sequentially from the top to the bottom.Until if battery voltage is below 11.83 volts then only the red LED that lights up which means that the charge batteries are empty. Even this red Led will die if the stress continues to drop to below 11.5 volts. The working principle of this circuit is a comparison of battery voltage with a reference voltage.
Schematic Battery level indicator
Saturday, December 7, 2013
9 Channels Sensor Switch
This sensor switch circuit diagram is designed using CMOS components. This sensor switch circuit has nine channels and consist of only three integrated circuits and some resistors. Due to high input impedance, 74HC147 allows to use of 4.7 M resistors to create a logic level "high" to sensor inputs. When one sensor is touched, the resulting low resistance to ground circuit causes IC1 to read a logical level L.
9 Channels Sensor Switch Circuit Diagram
If several sensors are touched simultaneously, priority encoder delivers 4-bit code corresponding to the sensor with the highest number.
9 Channels Sensor Switch Circuit Diagram
Friday, December 6, 2013
Reducing Treble tone circuit
Treble reducer circuit above is an example of a simple circuit and is suitable to be used as experimental material and analysis of the workings of the circuit.
As I mentioned earlier the bass reducer series, this series actually has the same working principles with a series of bass reducer. Where these circuits utilize capacitors nature of the charge and discharge. The difference of the damping function obtained from the difference of the capacitor. If the series bass reducer series capacitors are mounted on the op-amp input lines, while in this treble reducer series capacitors are mounted parallel with the strengthening of the op-amp prisoners. Installation of this circuit has a parallel in the work analysis in contrast with the installation of the series on a series of bass reducer. The difference is that the installation of the series, so we URLs that are easy to understand how a wire working capacitors for high frequency signal, so with high frekuesni so automatic signal to be passed to the output terminal by a capacitor. But if we put a parallel between the output capacitor with the terminals, then automatically because the capacitor is considered as a wire so the voltage on the capacitor is near 0 volts, so the output voltage will also follow the voltage on the capacitor because they connect parallel. As with the low frequency signal, the capacitor is considered open and makes voltage wire that fell to him is to approach the input voltage. To understand how the capacitor can be regarded as a wire or an open switch I mentioned in my post about the working principles of capacitors and a series of bass reducer.
Indeed, when examined in detail, not only the capacitors that play a role here but the component resistors and op-amp also affect. But I can confirm that the main function is performed by a capacitor reduction. Series resistors are intended to be installed that will flow into the capacitor can be adjusted so that it influences the charge and discharge the capacitor will make the appropriate damping.
Take a look at the picture above the treble reducer circuit and also the image output signal. There are two function generator as input and has a signal with different frequencies. The first signal of amplitude 1 volt and low frequencies, the two signals with an amplitude of 1 volt and with high frequency. At the time of our input select switch position to the relationship with the input low frequency signal, the signal output will be nearly equal to the input signal such as no change. Whereas if we switch position to link high-frequency input signal then the output signal amplitude will be damped near 0 volts.
Example treble reducer circuit is very simple and can you develop more in accordance with the desires and your needs. At least with understanding the working principle of this circuit we can apply a time when we are required to perform the function of damping trebele.
Thursday, December 5, 2013
Quad Audio Amplifier Circuit diagram with TDA7831 4×25W
Quad Audio Amplifier Circuit diagram with TDA7831 4×25WThe afterward is a cloister amplifier circuit (amplifier with four inputs and four outputs) based TDA7381. This amplifier is advised for car audio system, but you can additionally use this ambit for added purposes. This ambit has a architecture actual simple and actual accessible to build.
Wednesday, December 4, 2013
Honda Motorcycle CB750F Ciruit Diagram
Honda Motorcycle CB750F Ciruit DiagramThe afterward account shows the electrical base affiliation diagram for Honda Motorcycle CB750F. It shows the affiliation amid Honda genitalia such as the appropriate about-face arresting indicator light, oil burden admonishing light, aloof indicator, aerial axle indicator, about-face arresting indicator, tachometer lights, speedometer lights.
turn/signal active lights, headlight, about-face signal/running light, horn and horn button, clamp switch, advanced stop switch, about-face arresting ascendancy switch, dimmer switch, agent stop switch, atom units, aloof switch, oil burden switch, rear stop switch, fuses, agitation switch, amateur motor, battery, about-face arresting appropriate rear, appendage and anchor light, about-face arresting larboard rear, regulator/rectifier, alternator, agitation coils, beating generator, atom plugs, and additionally the blush code.
turn/signal active lights, headlight, about-face signal/running light, horn and horn button, clamp switch, advanced stop switch, about-face arresting ascendancy switch, dimmer switch, agent stop switch, atom units, aloof switch, oil burden switch, rear stop switch, fuses, agitation switch, amateur motor, battery, about-face arresting appropriate rear, appendage and anchor light, about-face arresting larboard rear, regulator/rectifier, alternator, agitation coils, beating generator, atom plugs, and additionally the blush code.
Tuesday, December 3, 2013
High HiFi Power Amplifier with MOSFET
Circuit amplifier "High Power HiFi Power Amplifier With MOSFET" is capable of giving the output power to the load speakers 240Watt and 380Watt 8Ohm to load 4Ohm speakers.
Voltage source to a series of power amplifiers "High Power HiFi Power Amplifier With MOSFET" This is a CT 25V 50V 25V to 50V CT of transformer CT. In making this power amplifier needs to be installed heatsinks on the power amplifier (MOSFET) in order to avoid excessive heat. The series of power supply to power amplifer can use the transformer 5A-20A and 35A mounted diode bridge and capacitors for a minimum of 2x 10.000uF electrolit. Details for the power amplifier circuit can be seen in the following figure.
High Power Series HiFi Power Amplifier With MOSFET can modify to increase power output by doubling the final power amplifier is based on the diiginkan. Power generated from doubling the final power amplifier will also double its power output of power amplifier circuit "High Power HiFi Power Amplifier With MOSFET" it.
Monday, December 2, 2013
Black Box Lightshow Circuit
Black Box Lightshow Circuit Heres the circuit for the Black Box Lightshow. Im pretty sure its right. And now, an explanation: The LED array is shown here as individual diodes, though I used six 5x7 LED arrays, each one is 2" tall.
They are arranged as 14 rows and 15 columns. The left channel is 8 columns and the right channel is 7 columns. The extra column from the left channel is the center column and gives nice symmetry. Not shown here is that on the right channel, the first column (pin 1) is not used so that the other columns are equal. The LM3914 is a Dot/Bar Display Driver.
It does all the heavy lifting of converting the audio signal into a series of bars - these are typically used as digital meters. The potentiometer sets the sensitivity of the display. Since the rows are multiplexed (see below), each column is only driving one LED at a time. I only show the left channel here, the right channel is identical, and they share the level setting potentiometer. The right portion of the diagram is a 555 clock, a 7493 4-bit counter and a 74154 4-to-16 line decoder/demultiplexer.
This is the "sweep" part of the display that cycles through each row of LEDs. The potentiometer at the top controls the sweep speed. The net result is that the 74154 is cycling through the pins/rows, grounding each in succession. Note that I only have 14 rows, but it is counting to 16 each time. No big deal, it doesnt affect the perceived output at all. The N2907 transistors are there to provide enough power for all the LEDs. Potentially, all 15 LEDs in a row can be lit up at once, so the transistors make sure there is enough juice. Unfortunately, I lost the original plans during a garage cleaning after I built the electronics (the box took another few months before I got around to it). I opened it up and reverse engineered my own work. I wont guarantee it, but it sure looks right to me. The one weird thing I found is that I dont have power going to pin 8 of the 555 (as shown here), but it works fine - go figure. Also, Im not 100% sure I got the polarity of the LEDs right, sorry about that. I would recommend testing that out first.
Sunday, December 1, 2013
BTL Stereo Amplifier TDA7052 3
This is BTL stereo power amplifier with basic amplifier on IC TDA7052 / TDA7053
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