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Press the button to produce a constant tone from the speaker. It's great for practicing Morse code. Close the switch and you have a police siren where the pitch rises as you press the button and falls when the button is released.
Components: 6 resistors, 3 capacitos, 2 diodes, transistor, IC, speaker, push button, slide switch, battery snap
Principles taught: 555 timer, voltage controlled oscillator |