This sensitive circuit was found in an Electronics Hobbyists Handbook from the 1990s. The circuit can use common general-purpose transistors in place of the original ones.
This basic oscillator with tunnel diode generates a 100 kHz signal with 1 uW output power. The...
This amplifier for medium or high impedance magnetic headsets (above 200 ohms) was found in an...
This circuit provides precise signals of three frequencies, using CMOS technology. The integrated...