auto off for audio gear

Posted on Feb 5, 2014

The circuit consists of a sensitive LM358 based comparator, IC1A, which keeps monostable IC2A (a 4538) triggered as long as an audio signal is detected at the input. Via coupling capacitor C1 the circuit takes its input signal from the hot` side of the loudspeaker or headphones in your audio gear. The monostable will time out 2 s after being triggered, the delay being deter-mined by R6 and C3.

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