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DiscoverCircuits.com -- Hobby Corner
"Hobby Circuits for
your Hobby Projects"
Last Updated on:
06/19/2009 02:55:11 PM
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Basement Front Doorbell Beeper
Circuit
designed by David Johnson, P.E. |
| If you can’t hear your
front doorbell when you are in your basement, this circuit might work for you.
Whenever the front doorbell button is pressed, the hobby circuit will activate a loud
beeper positioned in the basement. This circuit takes advantage of the fact that in many
homes, the 24vac power transformer used to power the doorbell is located near the
furnace in the basement. A box containing the electronic circuit could be mounted
next to the transformer. |
| A small bridge rectifier
converts the 24vac into DC. The 100uF capacitor filters the pulsating DC from the
bridge to form about 30v DC. Three diodes are wired in series with the door chime.
Whenever the front door pushbutton is pressed, the door chime sounds. AC current
drawn b the chime is routed through the three diodes shown. The two diodes in
series forms a 2 volt voltage source, which is connected to an inexpensive
opto-isolator. The 2 volts across the two diodes is sufficient to turn on the
opto-isolator circuit, which routes DC to the gate of the ZVN4206 FET. When the
doorbell chime sounds, the FET turns on a piezoelectric beeper, drawing power from the
30 DC supply. Make sure the beeper you use can handle the higher 30v voltage. |
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Click on Schematic below to view PDF
version of this Circuit |
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