In this 2001 circuit we have the way to trigger an SCR with a phototransistor. The circuit appears elsewhere in this section, obtained from publications from different eras.
We found this simple oscillator in a publication for radio amateurs in 1974. The transistor can be...
This circuit was found in a 70s American documentation. The converter can be of any type and the...
This source of some amps for voltages up to 40 V was found in an Italian magazine Elettronica...