[EE] Sense resistor parallel value finder... Thing...

[James Newtons Massmind]

Take a look at
<http://www.piclist.com/techref/io/stepper/linistep/lini_tun.htm#calculator>

The current value you enter will translated into a value for a current sense
resistor and a way of making that resistance by combining one or more
standard value resistors in parallel will be found.

So if you are driving 2 amp/phase motors with the Linistepper driver you
would put in 2 and it would tell you to put two 1 Ohm resistors in parallel
to make a 0.5 ohm resistor for the current sense circuit. Not hard, but 1.5
amps needs 2/3 ohms which, as it turns out, is a 1 ohm resistor and a 2 ohm
resistor in parallel.

Is that useful? Is it "whiz bang?" <GRIN> Or did I screw something up
somewhere?

---
James.
 


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[Olin Lathrop]

James Newtons Massmind wrote:
> Not hard, but 1.5 amps needs 2/3 ohms which, as it turns out, is a 1
> ohm resistor and a 2 ohm resistor in parallel.

Note that if you do that, the power dissipation won't be even between the
two resistors.  With current sense resistors at high currents, power
dissipation is a serious issue, so this might matter.


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