This circuit was obtained from a 1977 FET manual. The circuit measures inductances using a signal generator as a reference. The range is from 60 uH to 60 000 H. The FET can be a BF245.
The CK722 transistor used in this circuit is one of the first commercial types in the world. The...
This automatic dimmer for incandescent lamps was found in a European publication from the 1980s. The...
This traditional doubler configuration with the 555 can be found in other articles on the author’s site....