i work as an aitomotive tech and we generally use voltage drops for testing rather than resistance readings.
There are some advantages. Volt meters are cheap. They are only accurate to 1/10th of an ohm however and so they are not very useful on low current circuits.
A starter cable will not show a tenth of an ohm but still have snough resistance to fail to operate. .01 ohms * 200 amps = 20 volt drop on a twelve volt system? 10.5 when cranking due to battery internal resistance?
In other cases we are plagued by bad connections that wiggle or broken wires in harnesses. Spread terminals all of which cause intermittent issues that are plague to diagnose.
Sometimes a conductivity enhancer like stabilant 22 helps.
I am womderinf if a milliohm meter may be useful in identifying poor circuit connections for sensors or evaluating the quality of wiring from end to end.
More information is better. .1 ohms is zero information.
Yeah there are complications but the very most complicated and difficult tests we do are with intermittent resistance issues.
Ideally I would want a meter that could output a voltage proportional to the resistance measurement to a scope.
This would enabl many resistance based transducers to be scoped as well. Such as thermocouples.
Something like one third of cars lemon lawed after repeat repair attempts are electrical problems.
Thanks very much for advice ome way or the other.
-Andrew
There are some advantages. Volt meters are cheap. They are only accurate to 1/10th of an ohm however and so they are not very useful on low current circuits.
A starter cable will not show a tenth of an ohm but still have snough resistance to fail to operate. .01 ohms * 200 amps = 20 volt drop on a twelve volt system? 10.5 when cranking due to battery internal resistance?
In other cases we are plagued by bad connections that wiggle or broken wires in harnesses. Spread terminals all of which cause intermittent issues that are plague to diagnose.
Sometimes a conductivity enhancer like stabilant 22 helps.
I am womderinf if a milliohm meter may be useful in identifying poor circuit connections for sensors or evaluating the quality of wiring from end to end.
More information is better. .1 ohms is zero information.
Yeah there are complications but the very most complicated and difficult tests we do are with intermittent resistance issues.
Ideally I would want a meter that could output a voltage proportional to the resistance measurement to a scope.
This would enabl many resistance based transducers to be scoped as well. Such as thermocouples.
Something like one third of cars lemon lawed after repeat repair attempts are electrical problems.
Thanks very much for advice ome way or the other.
-Andrew