Tonewheel

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A technology developed by Lorens Hammond in which the pitch for each note is generated by revolving a toothed wheel adjacent to a pickup comprising a coil and a permanent magnet. This induces a current in the pickup coil which alternates at the required frequency. The wheels are turned by a synchronous motor and the output from the pickups is amplified and modulated to drive the loudspeaker.

Compare with the Wurlitzer Electrostatic reed organ.