Interesting problem with the Defi White racer gauges.........
05-31-2008, 11:32 AM
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Interesting problem with the Defi White racer gauges.........
Connecting the typical wire to switch from day to night causes the gauge to flash from bright to dim. These gauges don't vary with the dash dimmer control that normally changes the dash light brilliance. They change from bright, day time, to dim, at night, with the lights on. The only way I can get it to work is by having my dash lights all the way up. I may have to wire these to a full 12v supply when the lights are on. That is what the directions state.
05-31-2008, 12:01 PM
#3
You can't easily dim LEDs with voltage. Normally to dim an LED, you use Pulse Width Modulation -
PWM. You apply full voltage to the LED, but quickly turn it on and off. You can get it to dim by decreasing the on time, increasing the off time, or both. You do this in the realm of milliseconds (20 ms on, 20 ms off will be 1/2 brightness). Is there a separate lighting power wire to the gauges? If so, drop me an e-mail...
05-31-2008, 12:20 PM
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Same method we control the DC motor in a forklift. Yes, there is a separate wire. Instructions....
say to put it to +12v. These gauges always have the LEDs on. They are on bright without power to the wire and dim with the wire to +12v. Aren't those LEDs in the standard Defi "D" gauge?
05-31-2008, 12:22 PM
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I did a test on these with a power supply before I installed them......
With the power supply I needed about 5 volts to switch them to night mode, must be current related with all the other lamps on that circuit.
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05-31-2008, 12:27 PM
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Don't know, generally an LED, which usually drops the same voltage as a standard diode.....
uses about 1 volt for full brilliance. Generally they will add a resistor in series. Somewhat like the one used for the ash tray. It has a resistor in series. Now that I think about it, I wonder if that LED dims. Just checked, it actually does dim, it looks like a standard LED.