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Help with resistors in series..

Gene621

Sep 27, 2012
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Sep 27, 2012
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Hi there.. I need a bit of help.. I need to drop the amperage from a 48w power supply from 3A down to exactly 2.08A. I need to know which specific resistors would get the job done wired in series. Many thanks!

-Gene
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Why do you need to "drop the amperage"?

Is it because you have a device that requires 16V at 2.08A? (I assume your power supply is 16V).

If so, then you need to know that the current is determined by the load, not the power supply. If it only needs 2.08A and that voltage, then that's what it will draw.
 

panda

Jun 25, 2012
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Jun 25, 2012
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i just learned this after buying my first variable power supply :D. the load will only draw the amperage it needs from the power supply no matter how high the setting for current is. turn up the voltage too high and you burn things :(.
 

davenn

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Sep 5, 2009
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i just learned this after buying my first variable power supply :D. the load will only draw the amperage it needs from the power supply no matter how high the setting for current is. turn up the voltage too high and you burn things :(.

yup thats right :)

Now for the next part .... do you know why turning up the voltage will cause things to burn out in a specific circuit ?

eg ... you have a 16V device that will draw 2 amps from a 16V power supply ... the PSU is capable of 10 Amps
now what happens if you turn the voltage up to 20V or say 25V ?

Dave
 
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