With its "genuine superheterodyne circuit" and "standard 22½-volt battery," the ... The Regency was the first transistor product for the mainstream. A relatively simple 12-ounce AM radio, ...

This two transistor AM radio circuit is also called “mini-radio”. It uses only 2 transistors and few passive components which makes is very easy to be constructed. Although the circuit is very simple, ...

Howard Armstrong didn’t invent the ZN414. Besides, it’s a TRF receiver, Tuned Radio Frequency, which was a step up from a “crystal radio”, and was the trend except for Armstrong’s receivers.