We obtained this circuit in a Maxim documentation from the 90s. The circuit is based on the MAX627. This circuit provides an output voltage of 12 V from an input of 4.5 to 12 V.
The transistors in this 1978 circuit can be BC548 and 1N4148 diodes. The electrolytic capacitors can be...
This shield circuit is suggested by Texas Instruments and can employ almost any optical coupler...
This circuit was found in an American documentation from the 90s. It consists of a variable with a...