Found in a publication from the 50's, this circuit uses a germanium transistor of the time. The power supply is simple.
This 12 V incandescent lamp switch with time delay can be found in old documentation. The SCR can...
With this circuit it is possible to control the frequency of a 555 astable, given by C1 and R1...
This conventional astable uses two NPN transistor and was found in a publication of the year 1968. The...