This circuit was found in a 1971s English magazine. We can still assemble it using BC548 transistor. The other components are common. The supply voltage of 6 or 12 V depends only on the relay.
The setting of this power supply is only 0.1%. We found it in a 1969 US documentation. Transistors...
We found this interesting transistor generator in European documentation from the 1980s. The...
The circuit shown in the figure uses two of the four operational amplifiers found on the LM324...