This shield circuit with an optical coupler was found in an 90s EDN. The circuit can be used with voltages from 0 to 600 V with the indicated component values.
We found this FET-stabilized circuit in an American documentation from the 90s. With the values of the...
Other operational amplifiers of the same family can be used in this circuit suggested by Motorola in...
This circuit was found in Japanese documentation from the 1960s. The coil must be 4 mH and the...