Re: A Quick Question

On Wed, 11 Jun 2008 14:04:06 -0500, Mark Olson <olsonm@xxxxxxxxxxxx>
wrote:

TomO wrote:

What I'll probably do is wire in a pot with a couple of clip leads to
determine what value actually satisfies the sensor circuit, then pull the
proper resistor out of my all-too-large supply of spare parts.

I spent many years in the consumer and industrial electronics repair
field, so I'm quite familiar with how to figger these things out, but
thanks for the quick reminder.

What does putting a tap into a cell of a multi-cell battery look
like? It probably looks like a voltage source more than it looks
like a resistor. So what I would do is put a voltage divider
across the battery and hook up to that. Apparently tying the
sensor input to battery voltage through a series resistor works
too, but the sensor is almost certainly designed to measure voltage
and compare it to a threshold.

Guesses don't count. And if that were the case, tehre woudl
be no cooncreivable reason to have it IN the battery, instead of at
the posts.

It's likely a thermistor, which is going to have a different
resistance when submerged in a liquid ( dissipating heat from it ),
than when dry. A constant trickle voltage of known value is fed to
it, and then the variation in current ( as controlled by the change in
resistance ) is sensed, tellin you 'hot - not submerged' vs 'cool -
submerged'.


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