Tone Generator – Ding-Dong Bell using IC 8021 and Transistors

jacky October 15, 2018 6 Comments

A simple “tone generator” is a cool circuit that everyone must build in their electronics learning process. We’ve designed this tone generator circuit using 8021 IC, two transistors (BC548 or C8050), a small speaker and some associated components. As you see, components are minimal and you don’t need to spend more than a small amount to buy all the required parts for this project.

Let’s Build our Simple Tone Generator

Here we present a simple and low cost tone generator circuit, a ding dong bell suitable for calling bell purposes.It is made around IC 8021. It is an 8 pin IC but only four pins are shown here. 8021 has an in-built circuitry to produce ding dong sound each time its pin 3 is pulled low. The sound is stored in a 4 bit ROM. A complementary-pair, two-transistor amplifier is used to amplify the sound to a fair level of audibility. A piezoelectric tweeter or an 8-ohm, 500mW speaker  can be used at the output.

Each time when switch S2 is pressed, ding dong sound is produced twice. If you try to press switch S2 a second time when the first ding dong sound is still being produced, it has no effect whatever and the two ding-dong bell sounds will be invariably produced.S1 is the ON- OFF switch. Assemble the circuit on a good quality all purpose PCB.Don’t forget to use an IC holder for IC 8021.

Tone Generator Circuit Diagram.

Tone Generator Circuit

We have more Tone Generator circuits in our website, that may interest you: Take a look:

1. Police Siren using 555

2. Whistle to Beep Circuit

3. Touch Controlled Musical Bell

4. Musical Horn Circuit

5. Multitone Alarm Circuit

    January 27, 2014

    i want to create sound of drum but i can not undastant to how to make this sound please give me adv,s

  • Seetharaman
    February 26, 2011

    Hi Sinclair kindly go through the following site you will get full data.

  • February 25, 2011

    I can find no data on the 8021-2 chip for the tone generator ding dong.
    Who makes it?
    How do I get a data sheet?
    Where is it available?
    What sort of sounds is it capable of producing?
    Could it for instance make a sound like a commercial doorbell a la “Avon calling”

  • patrick vaz
    January 18, 2011

    Hi Admin,
    Any circuit ideas for a ding dong bell, but should sound like in the church!!!


  • July 11, 2008

    circuit on a good quality all pupose

  • July 11, 2008

    dong sound is produced twice. If you

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