The heterodyne is basically an adjustable resonance device for electrical pulses. When triggered by the Wonder Bar switch, the motor in the scanner circuit gradually rotates the heterodyne, shifting its internal configuration through a progression of resonance frequencies. If an incoming electrical pulse frequency doesn’t match the resonance frequency configuration of the heterodyne, the heterodyne effectively “blocks” it. However, if the incoming frequency does match the heterodyne’s resonance frequency, the heterodyne allows the incoming electrical signal to pass through to the rest of the circuit. If the strength of this heterodyne-permitted signal meets or exceeds the minimum strength requirements originally set by the driver, the circuit shuts off the motor. By shutting off the motor, the heterodyne’s resonance shape locks into place, allowing a steady stream of that frequency’s radio signal. Finally, this signal stream is converted into sound by the speaker. From the driver/listener’s perspective, the turner moves, stops at the first intelligible station and keeps playing that station until it’s turned. Writer Bio
