A Super-Regeneration Detector

Author: J.B. Hoag

An alternating voltage from an external oscillator, whose frequency lies just above the audible range (say 20 to 100 kHz), can be applied to the grid of a regenerative detector which has been adjusted just to the point of oscillation. This serves to shift the operating C-bias back and forth, with the result that the circuit goes in and out of oscillation at the super-audible frequency. The additional regeneration which can then be obtained makes the circuit extremely sensitive. This circuit has been found to be a very useful circuit for the ultra-high frequencies, but its tendency to radiate strongly and to tune broadly has on occasion created serious interference with other receivers. It is desirable that a tuned r.f. amplifier stage precede such detectors.