[DMCForum] Re: Andrew's second dumb question of the evening

["Matt Spittle" <mds328@xxxxxxx>]

Learn to use your meter :)

You cannot check resistance when there is a power source in the
circuit.  I believe the way that it checks the resistance is by
applying a very small voltage across the two leads and then measuring
the current that is passed.  When you have another voltage source
"live", it will throw off that reading.

Matt
#1604


--- In DMCForum@xxxxxxxxxxxxxxx, Andrew <aos+yahoo@xxxx> wrote:
> So when I have no battery hooked up to the car and check resistance 
> between the main ground at the back of the relay compartment and the
skin 
> of the car (or to the negative battery cable), I see about 0.5 ohms. 
> Seems fine.
> 
> But when I hook up a battery (fully charged or not), this number
jumps up 
> to about 170 ohms.
> 
> What's up with that?
> 
> -andrew

---

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