# AC polarity detection

Posted on Feb 5, 2014

It should at least detect 230 VAC but it would be cool/informative for future readers if the solution could work in US and EU (approximately 120 VAC to 250 VAC). I did find this (non-isolated!) circuit, but I can not get it to simulate (the simulator complains that it needs ground or the LED blinks on both halves of the wave). Most current answers are leading me to believe one needs a reference.

Now I`m thinking, why not create one Something like a `virtual ground` or somewhere along that line Today I read that older single-phase watt/hour-meters will run backwards if neutral and hot are reversed. Why is this and couldn`t the reason for this behavior be used in a `equivalent circuit` that detects `reverse polarity` Also, I wonder: could a hall-effect sensor be used to recognize a unloaded `hot` wire, since a hot wire clearly emits a diversity of electromagnetic fields and elf radiation Are you trying to tell the wires apart, or are you trying to identify the half of the cycle when a particular one is at a positive potential relative to the other Chris Stratton Oct 11 `12 at 3:22 I want reversed polarity/phase indicator for single phase vac, using just hot and neutral, no ground and no tranny. I searched high and low for over a week, and the simulation indicates I`m on to something other than the known `3-led` circuit that uses ground that is of no use to me. zduk Oct 11 `12 at 3:51 Again, are you trying to tell the wires apart, or are you trying to identify the half of the cycle when a particular one is at a positive potential relative to the other Chris Stratton Oct 11 `12 at 3:53 @Chris Stratton: I`m really sorry, thought the question was clear. I`m trying to tell the 2 ac-wires apart. Put differently, I want to know what conductor has `neutral` and what connector has `hot`. Put differently, I want a indicator if...

Leave Comment

characters left:

## New Circuits

.

Popular Circuits

Phone line indicator using BF256B
AVR Programmer with ATMega8-16
Relay driver
Low frequency TTL oscillator
Sound activated relay
Ac-relay
Ac-To-Dc Converter
Police siren
Ultra Bright LED Lamp
Rotate a stepper motor using a computer
Hi-fi Audio Amplifier Circuit Design and implementation