Getting Temp Gauge to read Correctly

Rodeo Joe said:

Ok for arguments sake lets say I buy a box of these,https://www.ebay.co.uk/itm/150Pcs-100ohm-1Mohm-Vertical-PCB-Preset-Variable-Resistor-Trimmer-Potentiometer/402133290765?epid=12010873528&hash=item5da1030f0d:g:UW4AAOSwiFBeXL0T&LH_All=1
How on earth would a wire them in and why 3 terminals?

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TheMegaMan said:

The two terminals at the bottom of the pot are connected to each end of the appropriate value resistive track. The third terminal (the one at the top) is for the wiper that the adjustment screw will move along the track,
So you need to connect to the top terminal and one of the other two terminals - which one you use depends will determine whether the resistance increased when turned clockwise or anticlockwise.
It's not necessary but is more conventional to also connect the wiper (top) terminal to the unused track terminal as well. Doesn't really make much difference when used as a variable resistor, but might avoid it going open circuit if the track/wiper get dirty or bad connections over time.
The reason there are 3 terminals is for when the device is used as a potential divider, you apply the voltage across the ends of the track, and the wiper will vary between 0v and the supply voltage, depending on the wiper position,. But that's not really how you want to use it if you just need as variable resistor,
Hope that makes sense. Ignore it if it's no help!

Click to expand...

TheMegaMan said:

The two terminals at the bottom of the pot are connected to each end of the appropriate value resistive track. The third terminal (the one at the top) is for the wiper that the adjustment screw will move along the track,
So you need to connect to the top terminal and one of the other two terminals - which one you use depends will determine whether the resistance increased when turned clockwise or anticlockwise.
It's not necessary but is more conventional to also connect the wiper (top) terminal to the unused track terminal as well. Doesn't really make much difference when used as a variable resistor, but might avoid it going open circuit if the track/wiper get dirty or bad connections over time.
The reason there are 3 terminals is for when the device is used as a potential divider, you apply the voltage across the ends of the track, and the wiper will vary between 0v and the supply voltage, depending on the wiper position,. But that's not really how you want to use it if you just need as variable resistor,
Hope that makes sense. Ignore it if it's no help!

Click to expand...

Rodeo Joe said:

So if I understand that then in words of one syllable I connect the wire from the sensor to the top terminal and a bottom one to the gauge?

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