Build a Beeper Visual Indicator Circuit

Description

This entire circuit of beeper cum visual indicator is build and fabricated around two timer ICs and is configured in an astable multivibrator mode. The frequency generated by IC₁ is controlled by capacitor C₁. The output from pin 3 of IC₁ is given to input pin 4 of IC₂ and base of voltage amplifier transistor T₁ through resistor R₄. Flashing light is connected to collector of switching transistor T₂ and grounded through resistor R₇.

The output of IC₂ is obtained from pin 3 and is given to base of power amplifier transistor T₃ used to drive 8-ohm speaker connected to the collector.

Circuit Diagram

Note: LED can be replaced with 3V to 12V DC bulb after eliminating resistor R₇.

 

 

Parts

Resistors (all ¼-watt, ± 5% Carbon)

R_1, R7 = 330 Ω

R₂ = 6.8 KΩ

R₃ = 5.6 KΩ

R₄ = 47 KΩ

R₅, R₆ = 22 KΩ

C₁ = 100 µF/10V electrolytic

C₂, C₄ = 0.1 µF ceramic disc

C₃ = 0.01 µF ceramic disc

C₅ = 1000 µF/25V electrolytic

IC₁, IC₂ = NE555 (Timer IC)

T₁ = BC148B

T₂ = SK100

T₃ = SL100B

SW₁ = Push-To-On switch

LS₁ = 8-ohm loudspeaker

LED₁ = Flashing LED

 

Source  -http://digitacircuits.blogspot.in/2013/02/build-beeper-visual-indicator.html