We found this tube receiver in a 1950s Japanese publication. The circuit uses 5 tubes and has an RF amplifier stage for greater sensitivity. The power supply is not shown on the circuit.
We found this solid-state relay circuit that can function as a shield in a Radio Electronics...
We found this filter in a documentation for radio amateurs from 1974. The transistors could be the...
The power supply for this circuit, which we found in a publication from the 1980s, must be...