@Trainlover9943 posted:... The next issue is when I did the end lights in the powered car, when stopped, they do dim a very slight bit, not enough that you could really tell but if you look at it directly after it stops, you can see the change. Almost like the car has rule 17 lighting. I run the set at 18v but if I turn the voltage down a hair (to 17v) that goes away...
@Trainlover9943 posted:...
2. I used standard 3MM white LEDs with 330ohm resistors. Yes, all I did was replaced the bulbs with the LEDs.
If you simply replaced a PS2 6V bulbs with a 3mm LED (w/330 Ohm resistor) then the slight drop in brightness can be explained. PS2 boards drive the light outputs to maintain constant brightness in a lamp (vs. constant brightness in an LED). It gets techno-nerdy regarding the difference between RMS and Average. What happens is when the engine stops, the average voltage applied to a PS2 light output drops slightly even though the RMS stays the same.
As to why the effect appears demoted at ~17V instead of ~18V gets even more arcane so I'm going to leave it at that.
The effect can be seen more dramatically for guys running PS2 conventional where track voltage varies widely. That is, the lamps maintain constant brightness over the conventional voltage range but if you replace a lamp with an LED (plus resistor), you will see a change in brightness. It's not a dramatic effect but is there nonetheless.
If it's critical to maintain constant brightness in your PS2 LED+resistor light output, it would involve adding maybe 3 or 4 components to regulate the light output to maintain a constant average voltage rather than a constant RMS voltage. It's not that it would be expensive (maybe $1 per light output) but I think somewhat tedious...in my opinion of course!
