This SCR relaxation oscillator was found in an 80's Electronic Design. It flashes a small incandescent lamp in frequency that depends on the capacitor.
This circuit was suggested in a 1976 documentation. We can use the pair BD135 and BD136 on the...
The original application of this 1967 Ferranti circuit can be changed so that it functions as a pass...
This source whose voltage depends only on the zener diode used, can supply currents up to about 3 A....