Door bell circuit using 555 ic

The main part of this doorbell circuit are two NE 555 timer ICs.When some one presses switch S1 momentarily, the loud speaker sounds a bell tone as long as the time period of the mono stable multi vibrator built around IC1.

When the switch S1 pressed, IC1 is triggered at its pin 2 and output pin 3 goes high for a time period previously set by the values of POT R4 and POT R5. When the output of C1 goes high it resets IC2 and it starts to oscillate to make a bell sound through the speaker.The IC2 is configured as an a stable multi vibrator whose oscillation frequency can be varied with the help of POT R5.By adjusting the values of R4 & R5, modifications on the tone are possible.

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