Found in Popular Electronics of January/February 1969, this transmitter has a few meters range and can be used as a wireless microphone.
Usiing that common diodes can oscillate, this circuit was given. The magazine that published it is...
After starting, this circuit turns off the relay in a time that depends on the 4020 pulse-count. This...
This circuit was taken from a Popular Electronics from January 1967. Transistors are from the...