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

crystal Op Amp Radio
Driving a Bipolar Stepper Motor with Arduino and ULN2803AG
4017 based sequencer
Metal detector schematic circuit using CS209A
Low Cost Analog to Digital circuit
Trap MC33171
Sequential Actuator for powering up to four devices



Top