We found this simple protection with zener diode in a 1967 Motorola documentation. The zener diode is 18 V, but the components can be changed for operation with other voltages.
So This circuit was published in a 1982 English magazine, but can be easily assembled using BC548 for...
With this circuit it is possible to tune an AM signal using a 5k potentiometer (4k7). The circuit was...
This power source was found in a 1968 Electronics World. The transistors are from that time. The...