On 10/15/2020 11:31 AM, %% wrote:


"TimR" wrote in message
...
On Wednesday, October 14, 2020 at 11:10:41 PM UTC-4,
wrote:
Amazon got me in an ad but this looks cool
https://www.amazon.com/dp/B074LSSD94?ref_=pfb_4g42mgjkd79227jheh2h2cm08cdh&t ag=fbcmapdsc-20&ascsubtag=pfb-P11-V01-O3-cjxk4o-S1YMNF


https://tinyurl.com/y33teyqs

Non contact volt METER (not just test light) with an laser aimed IR
thermometer.
$40

How is that possible?

Hall effect sensor for the AC voltage.


https://www.ecmweb.com/content/artic...oltage-sensors


https://theorycircuit.com/non-contac...ector-circuit/


That's one way to to it. Other designs use a FET on the front end or an
op amp. Some add a 555 to get blinking lights.