I have a circuit here which generates a loud alarm , a very loud alarm, using a piezo transducer. The sound part of the circuit is the following:
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  • I would like to ask firstly, why is there a 3 pin inductance? Is there any technical reason as to why a 2 pin inductance cannot/should not be used?
Inductance from point a to b is around 85mH and b to c is around 100mH and a very little inductance between a to c.
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There is an 8 pin IC which is feeding in the following waveform through a diode to the base of the transistor.
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The name of the IC has been erased by the manufacturer.
  • Does anyone know what IC this could be OR how to generate this waveform?

The whole circuit is running on two AAA batteries.