History
The heyday for grid-leak detectors was the 1920s, when battery-operated, multi-dial tuned radio frequency receivers using low-mu triodes with directly heated cathodes were the norm. The Zenith Models 11, 12, and 14 are examples of these kinds of radios. When indirectly heated cathodes and AC powered receivers were introduced in 1927, most manufacturers switched to plate detectors, and later to diode detectors.
Although the regenerative grid-leak detector was one of the more sensitive detectors of its day, its ability to radiate radio frequency energy when improperly adjusted limited its use in urban settings where multiple receivers would be operated in close proximity. The RCA Radiola III and IIIa and the Crosley Model 51 are examples of regenerative receivers from this period.
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