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Circuit Diagram · Doorbell · DIY Electronics

Two-Transistor Calling Bell Circuit

Type Circuit schematicStandard IEEE Std 315 / ANSI Y32.2Engine schematex-circuitUpdated 9/26/2026
Two-Transistor Calling Bell Circuit
Drawing preview
The scenario

A visitor presses the doorbell button, energizing the astable multivibrator, which oscillates and drives the speaker to produce a ringing sound.

What is in this drawing

Read the decisions behind it.

01

Using a two-transistor astable multivibrator for a self-oscillating tone without an IC

02

Placing the pushbutton in series with the battery to power the circuit only when pressed

03

Coupling the speaker through a capacitor to avoid DC bias

When building a simple, low-cost electronic doorbell or call alert using discrete components.

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