jow voltage battery beeper

[kishoretvk]

hello guys
please do help me to develop theory on the circuit below i need to explain for a semnar

the circuit lies in the below url

please telll me wat theory is needed to explain the ic's 555 timer n the transistor working there
how is the duty cycle changed


Battery Low Voltage Beeper

my maill id iskishoretvk9@gmail.com

**broken link removed**

 

[MikeMl]

Read

 

[kishoretvk]

k

i got most of tat but can i know the operation of the diode there in the circuit
please n thanx for ur sujestion

 

[blueroomelectronics]

You want us to do your homework for you?

 

[Hero999]

This looks like an over complicated way of doing it.

This simplest is to use an LM311 and a pulsed piezo buzzer.

If you must build your own oscillator, then I'd opt for a quad LM339, configure one as a low frequency oscillator, the second as an audio frequency oscillator and the third as a comparator.

I don't see any reason why this should require more than one IC plus a voltage reference.