Can someone please tell me the identity of this 7 segment display [Sorted]

Other Hardware General Electronics
1

I've a seven segment display made by Fairchild. I've had it for donkeys years, still in it's original package. It carries the number ND10402-531. It is very small, approx. 5mm * 6mm with 9 legs, not pins, as they're about 10mm long.
One row of 4 legs at the top, another of 4 legs at the bottom and the ninth leg in the centre.
Googling it brings up nothing relevant.

I presume the centre pin is the common one, but is it common anode or common cathode?

2

Do you have a multimeter?
You can use the diode test function to bias the pins and find out by process of elimination.
It's not unusual that an ohmmeter can provide enough current to, likewise, dimly illuminate the LEDs.

3

[quote author=Runaway Pancake link=topic=225512.msg1631906#msg1631906 date=1394679853]
Do you have a multimeter?
You can use the diode test function to bias the pins and find out by process of elimination.
It's not unusual that an ohmmeter can provide enough current to, likewise, dimly illuminate the LEDs.
[/quote]I've a digital multimeter, but it has no diode test function. I never thought of using it. Thanks for the suggestion.

4

You may have to select the low ohms range (or lock it there if you have an autoranging meter.)

5

Hi, can you supply a picture of it , possibly with a ruler in the pic.

Thanks Tom.... :slight_smile:

6

JohnLincoln:
Ha, I Googled "Fairchild ND10402-531", and it came up with just 1 result!, this page. XD

I told you there was nothing on google...

Runaway Pancake made a good suggestion, but if your multimeter's ohms range doesn't provide enough voltage and current to dimmly light the individual segments, then you could use a couple of AA cells and a series resistor to "investigate" the connections. That voltage should not cause any damage if you have a reversed connection.

Yep. That's exactly what I did, using a couple of slightly discharged Ni-MH cells (2 * 1.2V) and found that, as I suspected, the centre leg is the common (-ve) one. Now all I need is to find a socket for it or a small piece of stripboard or protoboard with a 1mm pitch! :fearful:

7

TomGeorge:
Hi, can you supply a picture of it , possibly with a ruler in the pic.

Thanks Tom.... :slight_smile:

I'll try to do that tomorrow.