Flicker Free lights using a Super Capacitor and Fibre Optics.

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Lights in passenger coaches and vans have the annoying tendency due to their light weight and possible poor track pickups, to flicker while operating in a moving train. Using a similar circuit as the one below will reduce this flicker completely in LED installations in vans.

The circuit below is from a U.S. modeller, Jim Betz, email Jim at " jimbetz@nospam.jimbetz.com (remove nospam to use) " and he will supply all the parts in a kit and it is very cheap. All parts can be purchased from Jaycar Electronics here in Australia.

This circuit can be used on both DC and DCC to power all the LEDs and will allow any form of cheap easy pickup to be used (see photo). This circuit could be tried on a passenger coach with incandescent lamps but due to their higher current requirements may require more capacitors or use the 1 farad Super Capacitor that is now available. Also if passenger coaches with lamps that are causing problems with booster circuit breaker resets (see below) this circuit could be modified to supply the lamps.

This circuit if used on DC is not polarity dependant. If requiring directional tail lights on a guards van, some form of switching selecting one of two LEDs that will have the fibre optic cables attached to. This will be left to each individual to determine how to do this.

Incandescent lamps draw 15 to 40 mAs and LEDs only draw, 2 – 5 mAs if high intensity LEDs are used by adjusting LED “series” resistor. In passenger coaches incandescent would better due their better overall 360 degrees radiating pattern where as LEDs have a very directional beam.

	The components soldered together and attached to the wagon floor or suitable location with Blu Tak. Blue cylinder is the Super Capacitor. Note: The black stripe on the zener diode is connected to the positive supply.
	Drill holes the same diameter of the fibre optic cable in the body where lights are to be located. 0.7 mm in this case. With the fibre optic cables located, apply the barrel of the soldering iron to mushroom over the end so that the cable does not “disappear” into the wagon.
	Drill 2 holes in the LED to locate the fibre optic cable. This must be a tight fit. Do not “super glue” the cables in the LED. Be careful not to drill too far into the LED body and damage the LED element. The resistor used for the LED is not critical. 1,000 ohms will be sufficient, but if using a few LEDs for coach illumination, you may need to increase resistance to decrease the current.
	Make some easy simple pick ups for the wagon. These do not need to be great as the circuit will compensate for poor power pick up. As shown, I used 0.4 mm phosphor bronze wire and just drilled a 0.4 mm hole through the bogie bolster. Solder wire to pick up and through hole to the bridge rectifier. Remember to have the axles reversed on the other bogie.
	This is the final product on the track and running around the layout, no evidence of flickering. See how you go.