SO I have a pair of ditch lights I'm adding to a GP30, and I want to simulate the slow fade of the large elements in the ditch light bulbs. I was thinking of using a capacitor wired in parallel, so that it only is used when the bulb discharges.
What do you all think, and have any of you attempted this? The ditch light flashing on most models I've seen doesn't look that real to me.
Julian
Modeling Pre-WP merger UP (1974-81)
fieryturbo I was thinking of using a capacitor wired in parallel, so that it only is used when the bulb discharges.
I was thinking of using a capacitor wired in parallel, so that it only is used when the bulb discharges.
Incorrect. It works for both ramp down and ramp up.
Capacitor when empty acts like a ground. This means just about all the energy goes to the capacitor and not the bulb. As the capacitor is filled the bulb gets more and more energy, getting brighter and brighter.http://www.tpub.com/neets/book2/3d.htm
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
What decoders and are you using light bulbs or LEDs? Some decoders do much better with LEDs than they do with bulbs, others have another CV to adjust when using LEDs vs when using bulbs to get the proper effect. Incandescent bulbs have the effect built in since the filament glow does not stop the instant current is cut off, LEDs need to be gradually dimmed via PWM because the LED stops glowing pretty much instantaneously when the current cuts off. TCS and NCE decoders have a CV that adjust the 'dimmed brightness' for LEDs and bulbs - the ideal setting for each is at the opposite ends of the scale. A little experimenting to get an optimal value, in the case of ditch lights, probably such that the dimmed light is actually not completely off, should yield the desired effect.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
The decoders are Digitrax SDH166D.