Description. A circuit diagram that can be used for the generation of CW Morse code is shown here. This circuit can be very useful those who would like practice Ham Radio. The circuit is nothing but an stable multi vibrator based on NE 555.The frequency of oscillations of the circuit depends on the components R1,R2 & C1.The circuit can be powered from a 9V PP3 battery. Circuit diagram with Parts list. Notes. The POT R2 can be used for frequency adjustments. POT R3 can be used for volume adjustments. The switch S1 can be a Morse code key.