This circuit can function as an output shield for microcontrollers, being compatible with TTL logic. The frequency is adjusted in the trimpot. TTL power is 5 V.
When the voltage exceeds the value given by the zener, this circuit from a 1990 documentation...
This circuit for the 11-meter band, operating at 29.255 MHz was found in a Radio Electronics dated...
Found in a Popular Electronics from the 9s, this circuit has output for RS-232 interfaces and current...