Schematic Reference

The above is a stereo amplifier circuit based on IC STK4191 with 2 X 50Watt output power 8 ohm impedance. And besides that you can use some of the IC can also be applied in this series include the STK4101, 4111, 4121, 5131, 4141, 4151, 5161, 4171, 4181, and 4191. Required supply voltage from 12 Volt to 35 Volt DC.

This is an old amplifier, LM383 is discontinued, so this LM383 ability be difficult to find. You can use ECG1232, TDA2002 or TDA2003 as the alter for LM383. Take a agenda that a heatsink bowl is appropriate to abstain overheating on the ICs.

Elco testing small to use AVO meters. But to distinguish between the elco elco 20.000uF/50V 2200uF/50V size would be very difficult, perhaps this phenomenon that makes creative hands itch to make elco with two label values.

Elco tester circuit

• Make sure the position of the switch (SW1) on the discharging position (position A).
• Connect / elco pairs that will be tested, then empty the contents briefly elco by pressing SW2 (approximately 1 to 3 seconds).
• Position the switch in the charging position (position B), the LED will light with a certain time (depending on the value elco). Hold in position B until the LED is not lit (elco is full).
• When the LED is not lit, immediately moved to the position of discharging position (A), the LED will light with a certain time (depending on the value elco tested). Hold in position A until the LED does not turn on again (fill elco is empty).
• The conclusion is quite simple, the larger the size elco, the longer the charging time and dischargingnya (old LED lights up). To calibrate it, readers can use the benchmark elco 10000uF size that can be justified. Only by logic alone writers think readers have understood.

The above is a stereo amplifier circuit based on IC STK4191 with 2 X 50Watt output power 8 ohm impedance. And besides that you can use some of the IC can also be applied in this series include the STK4101, 4111, 4121, 5131, 4141, 4151, 5161, 4171, 4181, and 4191. Required supply voltage from 12 Volt to 35 Volt DC.

This circuit is also use operational amplifier IC LM324 to drive the VN64GA with the error signal and to control output voltage. This output voltage is pulsating DC , which is quite satisfactory for battery charging. This circuit also can be converted to the system regulated DC supply.
You do this by increased C2 and anoother electrolytic capacitor is added across the load. The respon time is very fast, determined by the op amp.

Schematic and troubleshooting below :

• AC cable disconnected
• Transformer is damaged or leaking.
•  Broken or leaky diode.
• Installation of inverted foot elco.
• Instrallation of the components of the upside , particularly on the transistor , examine the placement of the feet emitter , collector and base.
• IC damaged.
• Soldering is less sticky.
• Line PCB damaged.

Audio Stereo Channel Selector Circuit

This circuit has accouterment for abutting stereo outputs from four altered sources/channels as inputs and alone one of them is selected/connected to the achievement at any one time.

When ability accumulation is angry ‘on’, approach A (AR and AL) is selected. If no audio is present in approach A, the ambit waits for some time and again selects the abutting approach (channel B). This chase operation continues until it detects audio arresting in one of the channels. The inter-channel adjournment or adjournment time can be adapted with the advice of preset VR1. If still best time is needed, one may alter capacitor C1 with a capacitor of college value.

Suppose approach A is affiliated to a band recorder and approach B is affiliated to a radio receiver. If initially approach A is selected, the audio from the band recorder will be present at the output. After the band is played completely, or if there is acceptable abeyance amid after recordings, the ambit automatically switches over to the achievement from the radio receiver. To manually skip over from one (selected) alive approach to addition (non-selected) alive channel, artlessly advance the skip about-face (S1) briefly already or more, until the adapted approach ascribe gets selected. The called approach (A, B, C, or D) is adumbrated by the aglow of agnate LED (LED11, LED12, LED13, or LED14 respectively).

IC CD4066 contains four alternation switches. These switches are affiliated to four abstracted channels. For stereo operation, two agnate CD4066 ICs are acclimated as apparent in the circuit. These alternation switches are controlled by IC CD4017 outputs. CD4017 is a 10-bit arena adverse IC. Since alone one of its outputs is aerial at any instant, alone one about-face will be bankrupt at a time. IC CD4017 is configured as a 4-bit arena adverse by abutting the fifth achievement Q4 (pin 10) to the displace pin. Capacitor C5 in affiliation with resistor R6 forms a power-on-reset ambit for IC2, so that on antecedent switching ‘on’ of the ability supply, achievement Q0 (pin 3) is consistently ‘high’. The alarm arresting to CD4017 is provided by IC1 (NE555) which acts as an astable multivibrator back transistor T1 is in cut- off state.

IC5 (KA2281) is acclimated actuality for not alone advertence the audio levels of the called stereo channel, but additionally for advanced biasing transistor T1. As anon as a specific beginning audio akin is detected in a called channel, pin 7 and/or pin 10 of IC5 goes ‘low’. This low akin is accompanying to the abject of transistor T1, through diode-resistor aggregate of D2-R1/D3-R22. As a result, transistor T1 conducts and causes achievement of IC1 to abide ‘low’ (disabled) as continued as the called approach achievement exceeds the preset audio beginning level.

Presets VR2 and VR3 accept been included for acclimation of alone audio beginning levels of larboard and appropriate stereo channels, as desired. Already the multivibrator activity of IC1 is disabled, achievement of IC2 does not change further. Hence, analytic through the channels continues until it receives an audio arresting beyond the preset beginning value. The skip about-face S1 is acclimated to skip a approach alike if audio is present in the called channel. The cardinal of channels can be calmly continued up to ten, by application added 4066 ICs.