View Full Version : Power for additional pressure sensor

19-02-06, 18:05
Help! I have what I think should a straightforward query but I can’t get an answer that I can understand.

I want to measure pressure drops in the intake system. Various discussions have led me to the conclusion that an additional MAP sensor would be just the job for plugging in to the pre-intercooler piping (for example). I could then take the output to a multimeter that I have which in turn can log the output voltage to a PC. I thought that it would be even easier to find a spare Greddy 3 bar pressure sensor as I already log the output from that to the Emanage and the volt/pressure relationships are known quantities.

However, I know nothing about electrickery and I’m looking for a simple answer to this question: “how would I supply the correct power level to an additional MAP sensor?”.

I don’t want to seem ungrateful to the people who have already tried to help but when people give explanations like this one below you hopefully begin to understand my problem:

“…to reduce a voltage from 12V to 5V you would need two resistors having resistance in the proportion 5/12 to 7/12, or 7 to 5. So you could choose 7 ohms and 5 ohms connected in series. Connecting the 7ohm resistor to the 12V supply and the 5 ohm to the earth will produce 5V between their junction and earth. However, their combined voltage of 12 ohms and the overall voltage across them of 12V means that a current of 1A will flow across them to earth (V / A = ohms, so A = V / ohms). The power generated will be 12W (W = V x A)…” :blink: :blink: :blink:

Is there any chance that some kind soul on here could explain to me, in terms that I can understand, the easiest way to supply the correct power to an additional 3 bar pressure sensor?

PS. If you understood that paragraph and felt like replying in the same vein please don’t bother as I won’t understand a word of it. I’m really looking for something like “take the blue wire from here and connect it to the square bit”. Ta.

Ian C
20-02-06, 01:57
Tap into the wires that power the stock MAP sensor :)

Simple enough for ya? :D


20-02-06, 06:20
At last - something that I can understand. Thanks Ian.