16 (25) Segment Display

[Mich...@aol.com]

Is this an awesome deal or what?

 

http://www.ebay.com/itm/201350574090

 

Mentioning because I think people might want to use as a test bench for smart socket?

 

Anyone have a circuit  made up to drive such a unit?  Would be nice to string a few together at that price.

 

Michail Wilson
206-920-6312

[gregebert]

The price is certainly enticing. It's multiplexed, but it's LED, hence low-voltage, so the driver is very simple. I would use a 5V supply, with PMOS or PNP devices to drive the anode.

For the cathodes, an NPN driver with an appropriate-sized emitter resistor will give you a constant-current driver. The datasheet says 50mA max per segment, so that would be a minimum of 50ohms for the emitter resistor assuming your logic runs at 3.3V (typical for FPGAs); 85 ohms if you run your logic at 5V. NMOS devices with low Vgs(on) are available, but you wont get current-regulation if you drive the gate at 5V.

Running LEDs from a supply less than 5V is possible, but I dont recommend it because LED and circuit variations will cause brightness changes, especially if you use just a series resistor instead of a current-regulator.

Running at higher voltages, up to 20V, is fine though it will result in more wasted energy (heat). Above 20V you have to be careful if you use NMOS or PMOS drivers because of the Vgs(max) rating.

I'm up to my ears in nixie projects, so I'm passing on this opportunity. Also, I'm not a big fan of segmented displays (yeah even if they are neon), though someday I do plan to make another clock with a 9-segment panaplex display I bought a few years ago.

The main reason I dont like segmented displays is the gaps between segments, particularly the ones with more than 7 segments. There's something about the fully-formed individual numerals that you get with true nixies that I find irresistible.

[Terry Kennedy]

On Wednesday, July 1, 2015 at 5:07:23 PM UTC-4, Michail wrote:

Is this an awesome deal or what?

 

http://www.ebay.com/itm/201350574090

Better hurry - only 2958 left 8-) 

[coggs]

The seller is in Greece. Probably distressed.

This clock's drive circuitry should be more than adequate for these smaller multi-segs

http://shop.evilmadscientist.com/productsmenu/tinykitlist/589-alphafivewhite

[Nick]

On Thursday, 2 July 2015 14:02:56 UTC+1, coggs wrote:

The seller is in Greece. Probably distressed.

This clock's drive circuitry should be more than adequate for these smaller multi-segs

http://shop.evilmadscientist.com/productsmenu/tinykitlist/589-alphafivewhite

He's selling in USD and Euros - he's insulated from all that. Anyway, the real problems for the Greeks haven't kicked in yet..

Nick (who has Greek relatives & friends living in Athens).