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Jezebels_couz Jezebels_couz is offline
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Default shunt/ current sense resistor question

On 12/2/20 8:10 AM, Bob Engelhardt wrote:
On 12/1/2020 9:41 PM, Jezebels_couz wrote:
In the process of finishing a 0-12 VDC @ 0-10 A switching power
supply. Fairly new at this and wanted to ask about the shunt
resistor.Â* It will be in the ground line.Â* Plans mentioned two
options: either a custom shunt made from constantan wire or similar,
or simply two 5W 0.1 ohm power resistors in parallel.Â* Since I wanted
to keep costs down, I am going with the power resistors, but I have a
concern:Â* I will be running 12 gauge wire for the output lines, but
when the ground wire reaches the shunt, even the two resistors in
parallel combined are far less than 12 gauge.Â* Should I be concerned,
or is the tiny resistor/ 12 gauge wire distance (basically just for
the 12 ga wire to resistor wire connection) irrelevant to heating and
losses?


12ga wire is 1.6R per 1000 feet*.Â* If your connection is 6", its
resistance is .0008R - 2% of your shunt & negligible.

* - https://www.engineeringtoolbox.com/c...re-d_1429.html


Here's a diagram of what I was trying to explain. I wasn't sure I was
very clear, so hopefully the diagram will better relate:

https://i.imgur.com/pYSRxiX.jpg