Audio operated relay

Posted on Feb 27, 2013

Ql and Q2 are general purpose transistors. The 10 K input pot is adjusted to a point just short of where Ql turns on as indicated by K pulling in. K is any 5 V reed relay. With the values shown for R (100 K) and C (47 µf), timing values from 5 to slightly over 5 seconds can be achieved

Audio operated relay
Click here to download the full size of the above Circuit.

B shows the addition of a 22 ? series resistor to the 10K input pot if a 12 V supply is used. A suitable 12 V reed relay must be used at K.

Leave Comment

characters left:

New Circuits



Popular Circuits

300W Subwoofer Power Amplifier
Brakelight Stop flasher
5 Mhz phase encoding
Logic test probe with memory
series robot circuit
pid controller Building a temperature-controlled water bath
audio sine wave generator
Momentary Switch Teamed With Latching Relay
telephone number display circuit diagram
ISL88731 SMBus Level 2 Battery Charger
Output input can be balanced equilibrium Repeater
Third harmonic excitation device automatic circuit a thyristor