Found in a 1968 Ferranti documentation, this circuit can be implemented with modern equivalent semiconductors. With the indicated components the load can be a lamp up to 1 A.
We found this circuit in the 1983 Radio Electronics Special projects magazine. The components are...
With the presented circuit it is possible to detect signals from transmitters in a frequency range...
This circuit was found in a British documentation from 1969. It can be implemented with modern...