This circuit was found in Motorola documentation from the 1980s. The components are of the time, not currently common as operational and opto receiver.
We found this circuit in an old American publication from the 1980s. Transistors can be...
For those who want to recover an old multimeter of this type, the circuit presented is worth...
This simple low-current charger does not use a transformer, having been found in a 2001...