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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View attachment 269769

Hey,
Im trying to use this to convert a signal wire for the holley terminator x for the speedo. It is the same concept in that it is a PWM- square wave output from the holley and i need a PWM+ 12v square wave for my dash. These pulses are at 8000 pulses per mile. My question is, will this work in this instance or will I run into issues with accuracy, signal degradation, or anything else. Thank you for your time and help with all this so far.

Moderator edit: New thread created from this.

 

PWM is the wrong term for this Speedometer-Signal.
It is a simple Variable-Frequency-Square-Wave which always has a 50% Duty-Cycle.
The "Pulse-Width" percentage is always the same and never varies,
but the Frequency of the 50% Square-Wave changes precisely with speed.

This Circuit will work IF You are absolutely positive that your Speedometer needs a 12-Volt-Signal.

If You are guessing or assuming ANYTHING You could smoke some very expensive equipment.

5-Volts is a much more common Input-Voltage and will "probably" work just fine.

If it works at all, then it will always be accurate.

Post the PDF Instructions for your Speedometer if You want verification from someone here.

A 5-Volt Version requires different parts.
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Hey,
Im trying to use this to convert a signal wire for the holley terminator x for the speedo. It is the same concept in that it is a PWM- square wave output from the holley and i need a PWM+ 12v square wave for my dash. These pulses are at 8000 pulses per mile. My question is, will this work in this instance or will I run into issues with accuracy, signal degradation, or anything else. Thank you for your time and help with all this so far.

Moderator edit: New thread created from this.

check this thread (https://forum.allaboutcircuits.com/...-a-pwm-or-12-14v-signal-2.189247/post-1765348)

I built this a few years ago (thx to a couple of guys on here) and worked great. I've also built a v2 of it now, that worked even better and has worked with multiple types of gauges including dakota digital.