Sensing line voltages

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You can't directly connect the AD of any microprocessor to the power lines of
your house and expect it to last more than a couple microseconds.

Dividing with resistors is not very safe either.

I found this reference to use an opto-isolator/ transformer connection to
measure a high AC voltage.

http://electronicdesign.com/article/pow ... tages.aspx\
?nl=1

Still looking for a simple over-current sensor.

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This circuit is to measure voltage.

How much current is over current ??

What do you really want to measure ?

don

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> > Still looking for a simple over-current sensor.

> How much current is over current ??
>
> What do you really want to measure ?

I get asked this from time to time, and it came up recently.

I suppose a small resistance (0.1 ohm) with a parallel bidirectional opto
isolator would work for a simple ocer-current sensor.

As I don't have a particular application in mind, but a typical use would be
with a 1/2 to 1 HP motor driven by a relay.

So throw me some suggestions.

thanks