On 2014-03-07, William Ray Wing <w...@mac.com> wrote: > On Mar 6, 2014, at 8:24 PM, Roy Smith <r...@panix.com> 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 gmail.com American a 55-year-old houseboy ... -- https://mail.python.org/mailman/listinfo/python-list