[Mini] Wiring instruments in parallel or series?

[Dr John C Bullas]

Greetings from FatBlokeRacing Pits

I have a quick question.... or two

1) Things like water temperature and oil pressure senders operate by
varying the voltage/resistance passing to earth through the sender for the
negative side of the gauge .....and this is use to displace a needle via a
magnetic doo-dads.....

If i want to measure whatever the gauge is measuring in the same way (and
knowing the range of the resistance over the 0-100 psi or 0-120c range)
will connecting another earth return wire to the sender, screw up the
readings?

Indeed could you tap off at the back of the negative side of the guage and
not screw up the readings?

The monitoring board would place a minute "load"  on the circuit I guess or
minute resistance

 https://www.flickr.com/photos/johnbullas/25258092774/

could this just go into the existing earth return wire to the sender?

Discuss......

FB




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