AC detection with schematic, could it be modified for TTL?

This circuit will detect AC line currents of about 250 mA or more without making any electrical connections to the line.

I'd like to use a single comparator or OpAmp with an output that could be connected directly to a PIC micro input. Also a 12V or 5V single supply device would be preferred.

Here's the page with the original document

**broken link removed**

You could probably use an LM311 - it's output is open-collector. Just use a pull-up resistor on the output to your +5v supply rail to set the logic "1" output voltage to 5v. When the comparator switches on, it's output goes to ground. Here's a link to a datasheet: https://www.electro-tech-online.com/custompdfs/2006/04/LM211-DPDF.pdf
JB

It's trivial to connect the existing circuit to a PIC, you simply need one resistor!.

I was hoping it would be as simple as using a different opamp and perhaps a resistor.

Therefore I could use an LM311 (or the quad version LM339) and a 22K or so pullup on it's output.

Thanks people, great forums.

just get an optical coupler and 2 resistors on the input to detect I then th output is your to to do whatever simple the isolation is 1000v or more why make complex of something so simple