LED Circuits

1n400X series. 4001 is fine but often you find 2s,and 4s common as higher voltage. Again, being honest, a 4002 is a little more margin of safety but not required.

I've standardized my diodes on 1N4003, a couple years ago I bought a thousand of these for 1 cent each.  Still working my way through them, though I can see I'll never get that price again.  I don't see any reason not to select the 1N4003 for the additional reverse voltage rating, it's no more expensive than the parts with a lower rating.

1n4001 rings a bell, maybe have been 1n4004.

Anyway,

I put some 1n4003 diodes in the cart.  ($.10 ea.)

My previous experience with LEDs and building lighting circuits was with G scale trains.  I also used diodes to step down voltage for slowing locos down on point to point layouts and built some simple simple directional lighting boards.

Not sure of all the applications with O scale but I'm interested in learning.  

This is typical of the going rate now at AliExpress.com, this is with free shipping.

If you're looking for diodes for motor voltage stepdown, I'd go up in current to at least to a 3A diode, this one has 600 PIV and a 100A surge rating, should survive motor voltage dropping use.  $1.80 with shipping for 20, so a whopping 9 cents each.

After placing my order for transistors and diodes I found my small parts tray from 15 years ago so I now have plenty of diodes, resisters and CL2N3s.

I also found a pack of 1.5CE36CA diodes which I believe are voltage suppression diodes. Is there a use for these when building LED lighting circuits / other small electronics boards for our AC powered trains?

I was working with G scale 24v DC at the time I bought them.

The 1.5CE36CA TVS diodes aren't really that useful for LED circuit, they're unnecessary.  However, if you're inside a powered unit or tender with electronics, it's useful to wire one of them across the incoming power from the track for transient protection.

Thanks John. That may what I did with them back in my G scale days.  

Ward