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Topic: Decrease line voltage by clamping (Read 1 time) previous topic - next topic


Why would a simple voltage divider not work?
Voltage divider requires one of the two resistors to be in series which means we'll have to cut thru the wire that will defeat the purpose


All hope is not lost. This sensor has a plug, doesn't it? You just need to source an identical plug and socket pair and insert those between the sensor and the ECU. That does the same thing as cutting the wire but it's unpluggable, if you want to pull your device off the car quickly and still leave it running.
"The problem is in the code you didn't post."


Nov 29, 2017, 02:47 am Last Edit: Nov 29, 2017, 02:48 am by Southpark
Why would a simple voltage divider not work?
It could possibly work. The main problem is that the description of the system isn't clear at all.

So far, we know there's a sensor that outputs some voltage between 0 and 5 volt, and this output voltage appears on a line (with respect to a ground). And the OP reckons he/she wants to change a 'voltage' dynamically. It's unclear 'which voltage' or 'what voltage' needs to be changed dynamically.....eg....the sensor's output voltage?

Or some other voltage along the line that could be sniffed with a big potentiometer that doesn't load the line down too much.


From what I can gather, I think you will find the OP doesn't just want a scaled down signal, he wants to at times amplify the signal, not get more than 5V, but say   2.6V for a 2.4V input.

That way he can re-map the MAP sensor to adjust ECU performance.

Tom... :)
Everything runs on smoke, let the smoke out, it stops running....


Nov 29, 2017, 04:15 am Last Edit: Nov 29, 2017, 04:16 am by Southpark
The OP does indicate reduction and clamping though. So maybe no amplification involved?

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