This circuit with 4 transistors can receive signals in 6 shortwave bands. The circuit is from a Radio Electronics from May 1958. The output is for high impedance headphones.
The frequency depends on the coil and is not found in the original documentation but should be...
This is a device for those who need to show that they know how to use digital electronics but have...
Using an operational amplifier with FET, this circuit from a 1977 publication can generate...