In the figure we have the way to implement a power zener diode. The voltage depends on the zener, and the maximum current of the transistor.
This circuit was found in an American documentation from the 60's. The transistors are from the...
This oscillator is indicated for the adjustment of FI of FM radios, having its frequency...
This configuration triggers an external circuit or simply an LED for time given by R1 and C1 (T =...