Simple multi-tone alarm circuit diagram sharing

This is the simple multi-tone alarm circuit diagram. This is a low-cost circuit, simple and easy to build. The main components of this circuit are based on dual op-amps MC1458 and LM380. The two op-amps inside MC1458 are used to generate square and triangle waves. LM380 is used to amplify the output. The first op-amp IC1a is connected as an astable multivibrator and the second op-amp IC1b is connected as an integrator to form the square wave triangle.

The two outputs square wave and sine wave can be selected using switch S1 to the input of IC2, which amplifies it to drive the speaker. POTR4 can be used for tone adjustment.

Simple multi-tone alarm instructions

IC1a and IC1b are identical. So their power supply is common. Pin 6 of IC2 (inv input) is not connected.

C1 and C2 are ceramic capacitors, and C3 is an electrolytic capacitor.

A bipolar power supply is needed here. All it takes is a center tapped transformer, a bridge diode, and an electrolytic capacitor. You can search for circuits on this site