Python programming

Grant Edwards invalid at invalid.invalid
Fri Mar 7 18:00:49 CET 2014

On 2014-03-07, William Ray Wing <wrw at> wrote:
> On Mar 6, 2014, at 8:24 PM, Roy Smith <roy at> wrote:

>>> I spotted a device on the table of the company calibration office...
>>> As I recall, it was a 100A capable resistor... 0.10 OHM.
>>> No idea what it was meant for; big binding posts at one end, and a
>>> slab of sheet steel in a "W" shape (smooth curves, not sharp bends).
>> External shunt for an ammeter?
> More likely a dummy load for power supply testing.

Could be.  Back when I was working on PWM controllers for golf cart
and small car motors, we used to use steel coathangers for test loads,
but once they got past orange and more towards yellow, they started to
get too soft.  An appropriately dimensioned chunk of sheet steel would
have been ideal.

> (Normally, ammeter shunts are sized to dissipate as little power as
> possible.)

I've used chunks of coathanger for that too, but I don't think the
resistance was stable enough over temperature to trust the results at
higher currents.

Grant Edwards               grant.b.edwards        Yow! If elected, Zippy
                                  at               pledges to each and every
                                American a 55-year-old
                                                   houseboy ...

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