Ok, I am converting a 50 Plymouth to 12 volt. No big deal normally, but as I always do, I used an instrument voltage regulator that was used through the 60's on Fords & Chryslers. I have used these many times with no problems, attach 12 volts to it, get appx. 5-6 volts out. I only need this to run the fuel gauge, as the others are mechanical. For some reason, this gauge doesn't like the way these regulators work. When we hook it up, the gauge goes up and down like I hooked it to a turn signal flasher. Now, basically, that is how these regulators work to control the voltage, just like any regulator. It's a mini set of points that get hot and open and close real fast. My first thought was a bad regulator, so I got a different one, and the results were the same. My next thought was it needed more resistance to make it go, so we hooked some light bulbs into the system. No change, just looked like a xmas tree. I'm thinking this gauge must be wound differently than anything else I've come across. To try and save my sanity, I hooked up a 49 Ford fuel gauge just to make sure I didn't have two bad units, and it worked fine. I then hooked a 6 volt battery to the Plymouth gauge and sending unit, and it works fine as well. I'm sure somebody has dropped voltage to their early Plymouth before, and at this point I would really like to here what the story is, and what I can use to make this thing work. Help save my brain, I don't have the answer!
how about you go to an electronics supply place and get a LM7806 voltage regulator, wire it up as shown on the package or find a data sheet on the internet if needed.(be sure to ground it) and it should be good to go.
I knew you would have some sort of answer Squirrel, but what would be the difference between that and what I already have, after all, what I am using is exactly what it is designed for, only it doesn't like Plymouth gauges?
the regulator you have is a thermal regulator, which is designed to work with a thermal type gage, not a magnetic gage. It does NOT provide 6 volts, it provides 12 volts, then zero volts, then 12 volts, etc. The electronic regulator will give you one amp of constant 6 volts....
I completely agree with your analysis and would only add that the old IVR would work on a properly damped gauge, but the early '50s Plymouth gauge responds too quickly to the fluctuations.
The other alternative I have seen here was to cannibalize a cell phone car charger for the voltage drop. Cheap!
How bout a length of resistor wire from an old early seventies car wire harness -you know back when they had points and wanted the voltage cut to 6-7 volts.....cheap and elegant...... I had a 38 chevy's fuel gage connected to 12 volts and worked fine with no failure....
A resistor will work fine, IF you happen to match the resistance to what the gage's resistance is. Then it will split the voltage in half. I've run the old 6v GM gas gages on 12v, they work ok, they're a bit "quick"....but they are designed to be accurate regardless of the voltage of the power source (within reason)
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