This simple two-transistor FM transmitter was found in the November 1991 issue of Radio Electronics magazine. The circuit has a 2 + 2 turn coil of 28-gauge wire with a diameter of 1 cm.
This oscillator has its frequency controlled by crystal and its frequency can be between 100 kHz...
This small crystal microphone transmitter was indicated in an 80s spy book. The range depends on...
The circuit shown is from the 1994 Linear Applications Handbook by National Semiconductor. The...