Using 4 tubes, this 1924 receiver combines new technologies as an intermediate frequency stage that was already beginning to appear. Listening is via phone and battery power.
This circuit was found in an Analog Devices publication from the 1990s. The circuit performs input...
This circuit is from a 1964 Electronic Design. The transistors are from that time. They can be...
Found in a 90s QST, this circuit uses an operational amplifier that is still common. It generates...