Thank you! This helped a lot trying to figure out ideas to get my Holley Terminator X Max (PWM-) signal for the speedo converted to an aftermarket Speedo Gauge! Holley told me I would need a solid state relay (15620NOS) to be able to do this (this honestly looks like what they did). But after seeing this, going to give this a try first for sure! Also 3D Printed an enclosure for it as well, just to be safe added a small (raspberry pi) heat sink. I had laying around as well. Any idea on what Pulse Per Mile, I should use in the Holley settings? I know it's currently defaults to 4000 (4k). Holley's 15620NOS say's it can only handle 1k, I'm just not spending the $80 to break it open and see.All You need is a "P-Channel" MOSFET, and 1 Resistor.
This FET is way over-kill, on purpose,
this will allow it to withstand wiring "mistakes", without getting instantly smoked.
You will also need to physically protect it, Heat-Shrink-Tubing will work great.
All Connections must be Soldered.
If this setup is used to Switch a significant Load, ( more than around 1-Amp ),
then it must be mounted to some sort of Heat-Sink,
like an Aluminum-Project-Box.
For more than a ~15-Amp Load, a heavier FET, and a proper Heat-Sink, should be selected.
Motor-Loads will need additional RFI noise protection.
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