Em 12/9/2011 10:34, Michael Watterson escreveu:
> Forrest Christian wrote:
>> I'm struggling with coming up with a circuit which I actually like for=20
>> measuring AC line voltage and current.   The goal is to be able to read=
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>> the voltage of AC line within a volt or two within a microchip PIC....  =
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>> For obvious reasons I'd like something where in normal operation the AC=
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>> line is isolated from the PIC side of the circuit.
>>  =20
> Neon and a photo transistor? Should work at about 200uA on  mains side?
> Voltage varies the current thus brightness due to large series resistor.=
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> Better suited maybe to 230V AC than 110V AC.
>
> Hall effect sensor to measure line current.


It seems that my suggestion got lost in the list:

"You could make a circuit with a small PIC (8 pins) with A/D converter,
connected directly to the AC line, powered by a transformerless power
supply and using a resistive divider to measure the line voltage. Then
transmit the result of the measurement to the other side of an
opto-coupler to a circuit that implement the remaining functionalities
of your appliance. This way you can read as many different signals as
you wish."


Isaac

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