This small regulator with transistors can supply 75 mA currents for charging NiCad rechargeable batteries. The circuit is from the 90s, using components from that time.
This circuit has the intensity of the signals controlled by the light that falls on the sensor....
The purpose of the diode in this oscillator circuit is to limit the amplitude of the output...
We found this ladder-shaped signal generator circuit in Radio Electronics magazine from August 1966....