We found this circuit in a 1978 documentation. The SCR conducts when the regulator's output voltage exceeds the zener voltage.
This oscillator is enabled when a high level is applied to the control input. The operating...
This circuit uses two oscillators to produce a sound that seems the sound of a ring-bell. The...
Found in a Popular Electronics from the 9s, this circuit has output for RS-232 interfaces and current...