A while back I saw an article in one of the magazines ( which I can't find now) about using a zener diode to drop 12 v. to 6v. for a gas gauge. All I remember was that the diode dropped the voltage to slightly below 6v. Does anybody know what diode to use? I think it was 5.7 or 5.8 v.
you could use an LM7806 instead? It's a voltage regulator. https://www.jalopyjournal.com/forum/threads/how-to-build-a-voltage-regulator-for-3.448589/ But to answer your question, no I don't know the recommended Zener diode voltage from the article that I can't find either.
I do not know the exact Professional Sounding answer to your question, but for years and years I have been using ordinary diodes such as you can buy at any Radio Shack to artificially make a high-low bulb out of single filament bulbs, AND a high/low tailight/brakeLight out of led third brake lights. Since the "ordinary" diodes I buy seem to all have a .4 volt drop, I put 4 or 5 in series, making a string of diodes that drop the voltage in a power wire to the light. That makes the "low" but still somewhat bright, Running Light. When I run a wire WITHOUT the diode string, I get the Bright light for brake or turn sig. I have been using that for years and years to make "third brake lights" into high/low lights suitable for Stop/Turn/Brake lights . For your unique question, you can try my method of stringing a few diodes in series, then measuring the voltage as you keep adding series diodes until you get what you want. There will likely be someone chiming in who knows just the right component/wordage to make it sound professional, but I just keep adding series diodes until the voltage drop is just what I need. My "rigs" (diode strings) last for years and years, so I am not worried about early failures due to being "less proffessional" than those who speak fancy terms...
I can do basic electrical work, lights, ignition and such but I have never seen anything like you're describing. Could you post pictures of what you did with comments, please?
What about the other gauges or are they mechanical maybe? I recall looking into a Runtz several years ago, was around 30 bucks I think, and you had to have one for each gauge. There was a early 70’s Dodge PU in the local Pick and pull so I snagged the reducer out of it. Fords used 6v gauges and a reducer through the 70’s as well.
IVR = instrument voltage regulator. I know Fords used them, maybe others. Drops the 12+ volts to the 5v range needed for the gauges. Early 60s models were basically all the same except for the mounting bracket. Uses spade terminal connectors. Later unit changed the connections to a snap like is used on a 9v battery.
This will do all the gauges. Been using them for years. No problems Oil, Gas, Temp Gauge Voltage Reducer with Hook Up Kit - MGR1K (vintageautogarage.com)
This is a similar solid state reducer from Amazon and eBay. Can be used to run 3 gauges per unit and is available in different voltage outputs.
I used the LM7806 that squirrel posted on my 49 Buick gas and temperature gauges. It has been working perfectly for about 8 years now. Cost about $3 per gauge to build them, maybe a little more now.
I have not used zeners this way but here is one rated at 6V 5W that might do the trick. https://www.mouser.com/ProductDetail/Central-Semiconductor/CZ5340B-TR-PBFREE?qs=u16ybLDytRaJqZ0ifs0uTQ== I think thats about as beefy as they come. EDIT: you would probably also need something like a 220 ohm resistor in series with the zener (then running its positive side to ground), and then pull off 6V at the junction.
The right information here, if you are using Ford King-Seeley gauges. Use a 59 Ford Ivr/Cvr. They can be bought at NAPA, if the counter man is Brite enough to look it up. As stated, later units used snap connections because of a printed circuit system.
Something else to consider is cell phone car chargers. If you look at the sticker on them the input is 12 volt, and the output is around 6 volt. I took one apart and used it to power a 6 volt gauge in a 12 volt car and it worked just fine. Plus you can find tons of them at garage sales and in the glove compartments of cars at the recyclers.
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