We found this circuit for video games in a Radio Electronics magazine from August 1977. The transistor can be any common RF type that reaches the desired signal frequency.
This crystal-controlled oscillator generates a 1 MHz rectangular signal and can be used as a time...
This' 90s circuit emits a signal in the FM band with a few tens of meters in range. The coil is...
This configuration, found many times on this website, is from a 1977 documentation. The frequency...