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This Morse code Practice Oscillator is a simple audio signal generator which is able to generate an audio tone at 750 Hz . It is actually a basic multivibrator oscillator which uses two transistors, four resistors and three capacitors. The circuit is powered from a 9V battery and we use a “homemade” push button as the “telegraph key”. We have built our homemade “telegraph key” using a small circuit board and a small piece of elastic metal foil. Since it is a very simple circuit and there isn’t any final power amplifier stage it can not be connected to any low impedance speaker. The output of the generator can only connected to a high impedance piezoelectric transducer. If you prefer a common speaker, you must add an amplifier stage.
Posted by: A.G
