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Digital Panel Meter Interface

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mark43

New Member
I am building a power supply (16v 6.6a) and would like to monitor amperage output
I have tried using resistance wire on the ground side (return to supply),
Measuring voltage drop across it. This works but I don't think this is the best way to do it.
So I got a current sensing shunt resistor (.1ohm 5watt) its good for 15A
I like this but, my amperage reading on the digital meter is off by.05A
how do I adjust the circuit to compansate for the error. Or do I need a different value shunt resistor.
I am a newbie to electronics, Please help.

Mark
 

Chippie

Member
The value of your series resistor can be calculated from :

the fsd of your meter, currently set to 2v

the max load current, e.g 6 amps.


from Ohms law we get R=V/I so,

2/6 =0.33333 Ohms and the power rating from V*I or
2*6 = 12 watts.......

Get the drift ?


BTW there's nothing wrong with using a series resistor in the neg or pos line, but try and make it as low as poss to minimise volt drop and dissipation
 

mark43

New Member
Sorry but I am confused.
The shunt resistor that I am using is good for 15A

https://www.precisionresistor.com/PLV5.htm
it is a 5w .1a 1%, Current sensing shunt resistor

My actual amp reading is off by .05a. I would like to adjust it so it is correct.
I am unsure on how to do this. This is my question.
I am a newbie to electonics, self learning,
It is easy to talk over my head.
Any ideas on how to adjust the circuit.??.
Do I need a .01a shunt resistor

Mark


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Sebi

Active Member
Configure the pnelmeter to 200mV, and apply 0.01 ohm shunt resistor. If the panelmeter is 3,5digit (unfortunately the link is dead), the max. readout is 19.99A.
 

mark43

New Member
Sebi,
So I got the wrong shunt resistor, I will try one that is .01a.
I have to order it, when I get it I will post the results.

Is there any way to adjust the exsisting circuit so it reads correct, Still using the .1a shunt resistor.

The links work I just cked them

Thanks Sebi.

Mark
 

Sebi

Active Member
Yes, in 200mV range You can calibrate it with other multimeter.
 

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