This circuit with unijunction transistors was found in a documentation from the 80's. The trigger times of the SCRs depend on the capacitors and are adjusted in the 5M (4M7) potentiometers.
This circuit is from an Italian publication from 1988 but can still be easily assembled....
We found this circuit in a Japanese publication in 1967. The circuit consists of a 15 W audio...
This charger circuit provides an initial voltage of 2.5 V and when the current reaches 180 mA the...