how to wire a pot

[fetzi]

hi,

i want to trim some maps with a potentiometer.
which should i use: 1k, 10k ?
and how should i wire it? which input?

thx.

regards
fetzi

[MarkMc]

Hi Fetzi,
A 1K pot will be fine but are you talking about a proper potentiometer like a Throttle Position sensor or just a variable resistor? The Pot would have three wires and you could wire it to an AV, a variable resistor will have two wires and will need to be wired to an AT.

Be careful, some of these devices may go to 0ohms at their lowest setting which will probably cause the input to go into error so you may need a resistor in line with it as well to give it some small voltage even at its lowest setting.

[fetzi]

hi mark,

thanks for your answer.

i talk about a 3-wire pot to trim for example ignition on a dyno.

pin1 : +5V
pin2: GND
pin3: AV

is this correct?

best regards
fetzi

[Scott@FP]

Usually on a pot (rotary or linear) with consecutive terminals A, B, and C its

A = 0v
B = signal out
C = 5v

if the signal is backwards say .5v @ full travel swap 5v and 0v.

[MarkMc]

It really depends on the pot, there is no real wiring convention so you should ask the people where you purchased the pot from.

As a simple check use your multi meter to find the two pins where no resistace change happens no matter where the dail is set, this is the 0v and 5v pins, the left over pin is the signal. If you put the pot to position 1 then the pin with the most resistance when measured to the signal pin is the 5v pin.