This receiver was found in a 1924 book by Gernsback. The circuit uses three tubes and is powered by 3 batteries of different voltages, common at the time.
The 1: 1 transformer on this circuit found in a 1967 Electronics World can be wrapped around a...
This simple stage can operate with low frequency signals (audio), driving a small lodspeaker....
This circuit has a gain of 6 and a Q factor of 8.63. Operational amplifiers are common, like the...