Theremin circuit is a device which generates musical effects in response to the capacitive proximity of a human hand.
This is the only musical instrument known to the writer that is played without being touched!
The Theremin is named after Professor Theremin who, in 1928, amazed New York audiences when he demonstrated his ability: "to obtain music from the ether".
How the Circuit Works
The instrument has two rods protruding from its housing, each one forming one 'plate’ of a capacitor.
The performer's hands become the second 'plates’ when held near the rods.
The capacitive changes engendered in one rod controls the pitch of the tone,the other rod responding by varying the amplitude of the output. simple experimental circuit is illustrated .
The plate should be around 30cm. square. It is placed next to a radio receiver tuned to a fairly strong station around 900 kHz.
The slug of the coil is then adjusted to obtain the most pleasing tone.
When the hand is moved near the plate,the pitch of the tone will change.
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