Placed near a common receiver, this oscillator is intended to generate a beating signal to receive RTTY or SSB communications. The circuit is from old telecommunications documentation.
This circuit from a Japanese publication in 1968 uses germanium transistors from the time like the...
In this circuit the voltage across the LED is limited by the diodes. The maximum current also...
Obtained from a 1980s Linear Technology documentation, this circuit has a hysteresis of less than...