Using a standard multimeter, this circuit from a 73 magazine for radio amateurs provides an output proportional to the inductance under test. The circuit is TTL and must be powered with 5 V.
This current meter with many scales was found in a 80s American documentation. The operational amplifier...
This dimmer, from an old publication, can use almost any triac and in shooting a neon lamp. The...
We found this circuit in a 1975 publication. The circuit can be made with more modern equivalent...