Found in American documentation from the 1990s, this circuit uses coils with multiple outlets to get the best reception, the diode is a general-purpose crystal diode.
This circuit was found in an old publication from 1989 but can still be assembled today with BD135...
We found this circuit in a 1987 documentation. Its purpose is to turn on a garage light using the...
In the figure we have a simple logic level indicator for TTL circuits or powered by 5 V....