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From the Technology Enhancement Programme (TEP), these circuits allow students to build a range of devices. Each circuit has a full circuit diagram, component list and explanation of how the circuit works. In this section, the circuits cover a range of sound and audio devices.

Two-tone siren
This circuit produces a sound similar to the sound produced by an American police car.

Noise switch
When sound impinges, e.g. snapping of fingers on the speaker, an LED will light and remain in that condition. i.e. the circuit is latched.

Electronic organ
An organ that can produce eight notes to play a simple tune.

Music IC
Used primarily in music boxes, toys and musical cards, when activated this circuit will play a popular ditty.

Jewellery box sound switch
When the lid of a jewellery box is raised, a popular ditty will be played.

Morse code trainer
This circuit can be used as a Morse code trainer. When a key or switch is depressed, the speaker emits a note at the same frequency as the dots and dashes transmitted in Morse code operation.

This circuit produces a sharp clicking sound at regular intervals. This is useful to keep time in music.

Two-way intercom
This circuit provides a means for two people (say in different rooms) to communicate with each other.

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Please be aware that resources have been published on the website in the form that they were originally supplied. This means that procedures reflect general practice and standards applicable at the time resources were produced and cannot be assumed to be acceptable today. Website users are fully responsible for ensuring that any activity, including practical work, which they carry out is in accordance with current regulations related to health and safety and that an appropriate risk assessment has been carried out.


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