- Tone Generator -

The 555 Timer

The 555 timer chip is an integrated circuit which is used to create a vibrating signal. It can be operated with a 5 volt power supply or with a 9v battery, and can be made to produce a wide range of frequencies. The frequency it generates is inversely proportional to the resistance and capacitance placed in the circuit.

Figure C2a
Tone generator circuit

A circuit diagram for a typical tone generator is shown above. Construct your tone generator on a breadboard. If you need more detail, you can look at a breadboard diagram or photograph. Attach a headphone jack where speaker leads are indicated, so you can listen to the tone which this circuit produces.

The Parts

The heart of the tone generator is an integrated circuit chip; the 555 timer. Other resistors and capacitors are need to control the frequency of vibrations produced. The list of parts suggests five volts, so the LVPS (set at 5 volts) will work well.

Test your Tone Generator by attaching earphones to hear the tone it produces. Now measure its frequency with an oscilloscope

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