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.
Suggested by Siliconix in 1980s documentation, this circuit uses currently uncommon components. The...
Figure bellow shows how n 4027 can be cascaded to form a divide-by-2. The maximum input frequency...
In the figure we have an interesting protection bridge against power polarity inversion of a...