3 ms·
You don’t need an optocoupler to measure grid frequency. You can just use a resistor. Dirt cheap, cheaper than a crystal.
by klodolph 6y ago
You don’t need an optocoupler to measure grid frequency. You can just use a resistor. Dirt cheap, cheaper than a crystal.
- garaetjjte 6y agoYes, but OP talked about isolated circuits. It's likely that most appliances don't need to be isolated though.
- klodolph 6y agoOP was talking about consumer circuits, I think they were mistaken about how likely they are to be isolated.