Saturday, September 13, 2014

Sound Activated Lamp Relay Switch Circuit

This simple Sound-Activated Lamp schema shown int the schematic diagram actives the switch using sound. We can use this schema for various applications, such as automatic (sound-controlled) disco light or car’s LED light show.  The Q1 amplify the audio from mic. The R1 is used to adjust the peak of signal to greater than about 0.7 volts, act as sensitivity adjuster. A certain level, the signal coming from microphone, after amplification by Q1, will trigger the SCR and light lamp I1. If we change the lamp with a relay, then we can get a sound-activated relay/switch, which can be used to control more powerful / high wattage high voltage lamps. If we use a relay, place a 1N4007 diode in parallel with the relay coil to prevent the back-emf from  relay coil destroying the SCR.

 Sound-Activated Lamp Circuit Diagram

 sound-activated lamp circuit diagram

1 comment:

  1. Could I modify this circuit to run off of a 9 volt battery to power a couple of flashing LEDs? What components would I need to change? Thanks!

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