Simple 5V regulator (CB8815E)

This simple 5.6 V regulator circuit was found in a 1966’s Philips. The zener can be changed to obtain other voltages.

4-Transistors MW Radio (CB18289E)
This 1956 direct amplification radio circuit was found in a documentation from Sylvania that...
400 Hz 741 Oscillator (CB17028E)
This conventional oscillator with the 741 can be precisely adjusted to produce a 400 Hz signal. The...
Crystal receiver with folder (CB8495E)
This circuit uses two diodes in a doubling configuration to receive medium-wave range signals. The...