Doorbell Warning Switch


Posted on Feb 4, 2014

This circuit will light a lamp at a remote location when the doorbell switch is pressed. This circuit should only be used with the solenoid type doorbells, the electronic type that play tunes will not work here. It is quite easy to miss the sound of a doorbell if you are watching TV, this circuit gets round the problem by providing a visual indic


Doorbell Warning Switch
Click here to download the full size of the above Circuit.

ation. As an alternative, a LED could also be used. You could just parallel a lamp across the doorbell, but this would mean extra drain from the doorbell batteries or transformer. A series resistor, R1 is wired in series with the doorbell and reduces current flow, thereby increasing battery life. The value of R1 is chosen so that about 0. 6 to 0. 7 volts is developed across it, when the doorbell switch is pressed. I used a combination of a 22 ohm resistor in parallel with a 50 ohm. The voltage drop across R1 is sufficient to switch on the transistor, the lamp in series with the collector will then illuminate. I also used an electromechanical counter in parallel with the lamp.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Ground tester
Video amplifier and video detector
transistors Mystery circuit: latching relay control with transitor / capacitor why doesnt it work
An Intel 8088 Maximum Mode Single Board Computer System
low power inverter using cd4047
555 new digital thermometer circuit diagram



Top