Audio – Alarm

You checked the transistor by measuring the resistance between the different pins. Sometimes it has problems, such as when measuring the resistance between the various legs correctly. But it does not work in the real circuit. Because while there is no measurement bias junction between CE. therefore, the detection transistor good or bad for sure. [...]

This is a siren sound generator circuit. Which is less expensive and can create simple. The IC1 is using CD4011 (Digital Nand Gate) and the IC2 is CD4046. Operation of the circuit, IC1 is a clock frequency 1 Hz.(Frequency adjusted by the value of R1 and C1.) Then it pluse IC1 regtifier through diode D1 [...]

This simple compressor circuit is suitable for use in a recorder tape from the speaker terminals of the receiver.This input can be changed from 200 mV to 6V. The output will remain at close to 5 mV. An attack time of the circuit for about 3 ms and release time of approximately 100 milliseconds, for [...]