
Important Note:
This circuit should only be used with
the solenoid type chime doorbells, the electronic type that play tunes
will not work here.
Notes:
The hardest part for this circuit was
the title. 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 indication, i.e. a lamp. 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.
Using a series resistor R1 actually reduces
current flow , and if run from batteries, will give them a longer
life. The value of R1 is chosen
so that about 0.6 to 0.7 volts is dropped across it, and the doorbell should
still ring. I used a combination of a
22 ohm resistor in parallel with a 50 ohm. The doorbell still rang and
circuit operated correctly. I used to
have an electromechanical counter that registered each time when
someone pressed the switch....in fact,
I remember a time when I had more "hits" at my doorbell then at my
web site=:)
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