Operating at a frequency of around 180 kHz, this transmitter was found in a Science & Electronics of 1970. The coil has 34 turns of 22 wire. The transistor can be the 2N2222.
This circuit was found in a 1967 Raytheon manual. The transistors are from the time. Equivalent modern...
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...
The circuit presented generates short pulses. This configuration was found in a publication from...