40A Stabilized Power Supply Circuit

This power supply is designed for amateurs, and has been in operation for over 10 years. Its design is simple and virtually immune to RF. It brings together the individual pieces, is the most expensive of 600 VA toroidal transformer, which can be replaced by another with different characteristics in the case of a voltage between 17 ~ 20V power and adequate for our needs.

Reference voltage of 7.5 V Zenner diode (6V8 8V2 ~), shall apply to Q2, which compares the input voltage divider consisting of resistor R5, R6 and VR2, address Darlington amplifier Q3, which is responsible for driving the output stage, which consists of a driver in Q4 2N3771 NPN transistor and 4 power, which can be mounted directly on the heat sink without insulation, since it is a grounded collector.

The source has a current limit (Q1), adjusted by VR1 and overload LED (DL2) and full short circuit protection, with zero consumption in case of short circuit can be maintained indefinitely in this state without danger.

(Please note that due to the great power of the power supply with a casual a short length of cable, high or small section that is strong enough to not exceed the maximum current of 40A. There can be regarded as a short circuit and cause the supply of a large amount of power supply energy).

active rectifier (D1, D2) is recommended for a screw type metal cathode on the floor, installing a heat sink large enough blocks. As the power transistors with such a high as possible hedgehog, without being isolated as above, may be part of the window of an aluminum frame. We also recommend the use of mechanical ventilation with the thermostat.

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Metronome Generator Circuit IC NE555

Here is easy circuit using IC NE555 which will be used to generate metronomes. Such a circuit is extremely useful to people who learns music. The circuit is nothing however an astable multivibrator wired around NE555 .The parts R1,R2&C1 determines the output frequency.

Notes.

• The circuit can be wired on a general purpose PCB or common board.
• The circuit can be powered from a 9V PP3 battery.
• The POT R1 can be used to adjust the rhythm of the sound.
• The POT R2 can be used as volume control.
• The speaker k1 can be a n 8 Ohm tweeter.

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Audio Selector Stereo 4 Channel

Audio Selector Stereo 4 Channel

This circuit is for connecting the stereo outputs of four different channels as inputs and only one is selected for output at any time.

When the circuit breaker on, the channel A (AR and AL) is selected. If there is no audio on the channel A, the circuit waits for some time and then select the next channel (channel B). The search operation continues until it detects an audio signal in one channel. The time delay between channels or wait can be adjusted with the help of preset VR1. If time is no longer necessary, you can replace a capacitor C1 with a higher value.

Manually jump from one channel to another channel active active, just press the jump switch (S1) to the desired channel input is selected. The selected channel (A, B, C or D) is indicated by the corresponding bright LED (LED 11, 12, 13 or 14).

IC contains 4 analog switches CD4066, these switches are connected to four channels. These analog switches controlled by IC CD4017 outputs. CD4017 is a 10-bit ring counter IC. Since only one of its products is high at any instant, only one switch is closed at a time. CD4017 IC is configured as a ring counter 4-bit by connecting the fifth exit Q4 (pin 10) on the reset pin. Capacitor C5, in connection with the resistor R6 form a power circuit-on-reset IC2, so that the initial change of the power supply, output Q0 (pin 3) is always high. The clock signal is provided by IC1 CD4017 NE555 which acts as an astable multivibrator when transistor T1 is in state court.

KA2281 IC5 is used here not only to indicate the levels of stereo audio channels selected, but also to bias transistor T1. As soon as a specific audio threshold is detected in a selected channel, the pin 7 and / or pin 10 of IC5 goes low. This low level is coupled to the base of transistor T1 through a combination of diodes D2-R1/D3-R22 resistance. As a result, transistor T1 conducts and causes the output of IC1 to remain low as long as the output of the selected channel audio level exceeds the threshold.

VR3 VR2 and Presets are included for adjusting each of the threshold levels for audio left and right stereo channels as desired. Once the action multivibrator IC1 is disabled, the output of IC2 is not changed more. Therefore, searching through the channels continues until it receives an audio signal above the threshold. Jumping the switch S1 is used to jump from one audio channel, even if present in the selected channel. The number of channels can easily be extended to ten by 4066 the use of additional integrated circuits.

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Audio Processor Circuit using SSM2045 IC

Audio Processor Circuit using SSM2045 IC

This audio processor ambit appearance the SSM2045 IC which was developed distinctively for cyberbanking music applications and the 741 opamp IC. The ambit is configured as a low canyon clarify with a DC voltage ascendancy for gain. The ascribe arresting is set to a alive akin of 150mVpp through the resistor R1.

The clarify has 2 buffered outputs: the 2-pole achievement at pin 1 and 4-pole achievement at pin 8. Internally, the outputs are affiliated to 2 voltage-controlled-amplifiers (VCA). The R15 and R16 are affiliated to these outputs to accomplish optimum account and ascendancy voltage suppression.

P4 is the aggregate control. The accepted that flows to the pins 15 and 16 should not go above the best of 250 µA. The antithesis of the two VCAs and the absolute clarify is actuality controlled be a voltage ambit of -250 mV to + 250 mV at pin 14. This voltage can be set by P2.

The ascribe can be apprenticed with antecedent impedances up to a best of 200 Ω. With an ascribe akin of 0dBm, the VCA weakens by 6 dB. The bent accepted bare at pin 17 is amid 120 µA and 185 µA. The blow abundance can be confused amid 20 Hz and 20 kHz with a capricious voltage at pin 5. This can be assorted through P1. The capacitor ethics were called to accord the clarify its Butterworth characteristics.

The achievement accepted of the SSM2045 IC is adapted to a voltage achievement by the 741 opamp. Any sybsequent ambit charge be DC decoupled from IC2. The noise-voltage allowance is about 80 dB.

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