I need circuit for an electronic bell. Pushing a button creates impulse which is causing a sound on the speaker.
When you push a button, it is generating a basic frequency (1 kHz) in impulses. The time of pause of impulse is lowering proportionally with a length of duration how long button is pushed.
Your circuit looks fine for the positive half cycle of the input A.C. signal
But what if the switch is pressed for the negative half cycle....
You need to get the replica of the same circuit below for the negative half cycle
Try to use the concept of Two diode rectifier
forget it,
as no one can push for a period equal to half period of 25mS . the concept of errakeshpillai appears theoretical.
but we need to more consider that after push is released, whether the frequency would taper down.
Depends on. A typical door bell uses a bell transformer, so the doorbell push is operated with safe extra low voltage. This is an option for your circuit as well.
for test purpose apply 6V DC from a wall brick or adopter.and have only a diode and electrolytic capacitor.
have the switch shifted to DC input point. Diode helps reverse protection, and capacitor the oscillator return for the signal.