Using a 4046 PLL, which is not very common nowadays, this circuit was found in the October 1994 issue of Electronics Now magazine. The power is provided by the transistor and is small in this case.
This simple timer, which activates an LED indicator, but which can be modified to activate a...
This circuit was obtained in a documentation for radio amateurs in 1974. The coil consists of 12...
This circuit was found in a 1973’s Japanese magazine. It uses transistors of the time and is...