Beeper Using 1C 555

Here is a `beeper` circuit employing two 555 ICs. It can be used in various circuits (having supply voltage of 5 to-15V DC) that require an alarm or a `beeping` signal. IC1 is connected in astable mode in the circuit in such a way that squarewave output at about 1 Hz is obtained. lC2is also connected in astable mode, but it gives an output with ab
Beeper Using 1C 555 - schematic

out 1 kHz frequency. The output of IC1 (pin 3) is connected to `Reset` terminal (pin 4) of IC2. So, the continuous I kHz tone of IC2 is interrupted by the I Hz signal from IC1, producing a`beep-ing` sound. Capacitor C4 is used to restrict DC signals. The circuit operates satisfactorily when it is to be activated by a relay or a mechanical switch, but when it is to be operated by logic ICs, such as CMOS or TTL ICs, a bit of modification is required. Instead of connecting pin 4 of ICI to Vcc, it should be connected to the output of the logic element through which it is to be activated. A logic`I`at pin4 will activate the beeper and logic `0` will turn it off. Rest of the circuit would remain the same.

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