During a canal boat holiday, my brother enquired what current the
starter took from the battery.

I found that my cheap pocket DMM would read the millivolts across the
earth strap when we turned on all the lights of known wattage; and it
would also read the volts across the strap whilst the starter was
turning. So we were able to calculate the starter motor current as
around 200 A whilst turning steadily (but not the peaks).

I forget how we strangled the engine (diesel) to stop it starting
during this experiment. Could we have let air in somehow? Maybe there
was a stop valve?

BillJ
(Edinburgh)

On Wed, 16 Jul 2003 01:34:28 -0700, Watson A.Name - 'Watt Sun'
wrote:

I got tired of switching the leads of my DMM. Suddenly if dawned on
me that I can just set the power supply to 10.0V for exaample, and
read the current, and then divide the voltage by the current to find
the resistance. Like I put a resistance on the PS, it reads 10.0V and
the current is .018A, so 10 / .018 gives 555.6 ohms. Must be a 560
ohm resistor.

I turned my PS into an ohmmeter - FREE!

Hee-hee - Work smarter, not harder!

Of course, make sure the current stays low so the resistance doesn't
overheat. For low resistances use a volt or less.