voltage drop across resistor ?

May 15, 2004 2 Replies
E

Hi all,



I built a current sence circuit which trips out at about 5amps using a a



0.1R Ressitor, Which should give around 400mV, which works fine. The problem is I can't for the life of me remember how I worked out the resistor value. I would assume that 0.047R would give me 400mV drop at 10amps though thats only a guess. So how do you work it out ?

thanks, Chris


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D

R (ohm) = U (volt) / I (amp) = 0.4 V / 10 A = 0.04 Ohm

The power that is used by the resistor can be calculated as follows:

P (watt) = U (volt) * I (amp) = 0.4 V * 10 A= 4 Watt

In this case at least a 5 watt resistor should be used.

hope this helps, Dirk

"exxos" schreef in bericht news:40a5d814$0$25320$ snipped-for-privacy@news-text.dial.pipex.com...

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E

thanks, was about the same as my guess :)

Chris

problem

value.

thats

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