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25th Feb 2021, 6:37 pm | #1 |
Triode
Join Date: Jul 2020
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 12
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Load resistor on low voltage power supply
Hi all.
I have a few load resistors lying around. I use them on DC power supplies, but am wondering if they would work on a low voltage AC power supply as well, say to test 0.5A on 19VAC supply. Thanks |
25th Feb 2021, 7:04 pm | #2 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,289
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Re: Load resistor on low voltage power supply
They'll work fine so long as they can handle the power. 8.5W in the example you quote, but obviously current and power will depend on the resistance.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
25th Feb 2021, 7:29 pm | #3 | |
Dekatron
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
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Re: Load resistor on low voltage power supply
Quote:
Sounds like this is from a simple transformer? What do you want the test to establish? It may be productive to monitor voltage when that current is passing - if that's the current you will be needing. Depending on the relative size of the transformer, the volts may 'sag' at full current, so worth checking that.
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Al |
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26th Feb 2021, 11:44 am | #4 |
Octode
Join Date: Jun 2013
Location: Fleet, Hampshire, UK
Posts: 1,765
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Re: Load resistor on low voltage power supply
Also worth bearing in mind that they will work for you just as they do on DC supplies, but only for testing purely resistive loads.
If you're making an AC supply, perhaps you're looking to work with inductive loads, in which case the maths gets more complicated than simple ohms law. Adam |
26th Feb 2021, 6:06 pm | #5 | |
Guest
Posts: n/a
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Re: Load resistor on low voltage power supply
Quote:
*complex numbers, not complex but A complex of two, just two, per number. Easy to see on graph paper, perhaps they should have been called graph or Cartesian (as in two dimensional) numbers. |
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27th Feb 2021, 11:34 am | #6 |
Dekatron
Join Date: Jul 2007
Location: Penrith, Cumbria, UK.
Posts: 3,687
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Re: Load resistor on low voltage power supply
Rectangular form, as opposed to Polar form, sounds less intimidating than 'complex'.
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