Looking for a small bridge rectifier and capacitor for use with an LED. I have been thinking about doing a lighting project in this n scale bobber caboose. The interior 14mm wide x 30 mm long x 10mm high. Has anyone done a lighting project for a small space like this? What model of bridge recctifier did you use?
Not sure if this helps but what I did for my turntable project... More about it here.... http://1fatgmc.com/RailRoad/Turntable/page-12.html I think I bought the bridge rectifier from Digi-Key but you can also find them from Ngineering ( HERE ). Sumner
Thanks Sumner, that looks like a good size. Do you remember what the part number was fro Digikeys? I was looking there but got overwhelmed with the number of items and could not find a sort by size option
I looked in my Digikey orders and didn't see it there I think I ordered it from Ngineering.... the top one ( Tiny Bridge) ( HERE ). The data sheet is there with I believe the part number but the prices and shipping aren't bad there. Sumner
Is there any special reason for a rectifier, and a capacitor? Just try with a led and a suitable resistor.
A diode in series with a resistor and LED will provide DC only to the LED. This will give a half-wave rectifier, not a full wave rectifier as is done with a bridge rectifier. But given the voltages used by DCC this will be more than enough with using just a diode. And if you really want to flatten the half-wave pulsed outputs then just add a capacitor, say 10 to 100µF. these can be had in a 1206 package, or any small package for that matter. They will withstand the rectified square waves from DCC.
Was also looking to be able to use this on DC power. That is why I put in the bridge rectifier. I guess I always could just put in two LEDs and no capacitor. But the caboose only has two axles so pickup may be spotty
The OnSemi (formerly Fairchild) MB1S full wave rectifier is $0.44 at Mouser, qty 1-9 pcs on cut-tape, >4k pcs in stock. I don't know what shipping would be, since they are practically down the street from me, and I can pick them up. Been doing business with them for a long time. A full wave rectifier does not need as large a capacitor for filtering out the residual AC. And it lays out nicely on the tiny circuit board, as Sumner showed.
I use a KMB14F Schottky bridge driver with a 1000uf 16v capacitor and a NSI50010YT1G 10ma LED driver. No resistor is required and depending on the LED , it will light with as little as 2v and the brightness will remain constant from 3v up. If a 1000 uf capacitor is to large, you can use a smaller one . The resistor is shown for size.
Yeah, that big a capacitor IS overkill. DCC (5-9 kHz square wave with ~4 uS rise/fall) will have VERY narrow nulls when full-wave rectified, and you're only drawing 10 mA. Visually, you could ditch the capacitor altogether, but for video, maybe not... I'd bet a 0.1 uF would do the trick just fine. By my rough calc (check me!) a 0.1 uF (100nF) cap will drop ~0.4V in the 4 uS null between rectified DCC pulses. Still overkill. 0.01uF (10 nF: 4V drop) would work plenty good 'nuf. Actually, those drops are 2x actual because the rectified DCC voltage drop between pulses will be a triangular notch, not a rectangular one, so half the area in the drop. Cool circuit; thanks for sharing!
in either case, the drop would not be enough to affect standard video recording, and you wouldn't notice it with the naked eye .. too short of a time base ..
