noload current

[audioguru]

I have had an American electrical/mechanical doorbell for years. It has two solenoids and the plungers strike a resonant bar of metal. It wasn't loud enough to be heard throughout my home. So i went to buy a better one and saw the same thing as I had. It was expensive.

I also saw a cheaper Chinese electrical/mechanical doorbell that has plastic resonant chambers beside the resonant metal bars and it works much better and is much louder.

Of course it is powered by a transformer. The transformer is cheap and is good quality.

 

[RODALCO]

Transformer

A bell transformer expensive, come on Fahime.

A 5 VA, 240 / 3 - 5 - 8 Volts transformer costs about NZ$ 10 or US$ 6.

That is not much to spend for a safe low voltage supply instead of burning down your house, or killing someone because of a faulty doorbell switch.

 

[audioguru]

It is a very big world. Things that are cheap and plentiful to some of us are too expensive and are rare to find for others.

 

[Fahime]

It is a very big world. Things that are cheap and plentiful to some of us are too expensive and are rare to find for others.

if people around you are stupid enough to use tranformerless supplies that's their fault.

It is not the place of discussing about countries. The point is that someone is going to make a battery powered doorbell,whatever the reason is. Is it obligatory to explain the reason of choosing the project? Remember we are here to assist not to disdain.

 

[Aily Sajjad]

Use a Monostable timer made of 555, and drive base of a transitor with its ouput. Connect Collector of transistor with 3V and emitter with circuit. Connect the push button such that it triggers the 555 every time its is pressed.


Aily.

 

[audioguru]

Why is an audio amplifier IC being used with the toy "ding-dong" 3V IC?
The output of the ding-dong is square-waves, isn't it?

The two-transistors DC amplifier on the datasheet will make the same low amount of power (100mW) and it and will automatically turn off.