A7001

[electrofish]

Hi

I have bought some A7001 nixie.

Cannot find any info but have a picture attached.

Any help appreciated

regards
John

[greg...@hotmail.com]

With any nixie tube, you can figure out the pinout yourself with a high-voltage supply (200 volts or more), and a series resistor to limit the current. It wont hurt the tube if you apply voltage to the "wrong" pins as long as you limit the current. I've done this many times when it would take me longer to go in the house to pull up the datasheet than probe it with this method.

Make sure the resistor is big enough to limit the current to about 1 mA. Tubes will have a voltage drop around 130V, so a 200V supply with a 70K series resistor will keep you safe. Use a higher resistor for higher supply voltages. Connect the resistor to the + lead on the supply. You will experiment with the - lead from the power supply and the other end of the resistor. Best to use clip-leads.

Pick any 2 pins. You should see something glow. If not, then it's possible you found an internal pin that's not normally used. Any nixie tube with more than 11 pins will have these.

If you see a numeral glowing, then the negative lead has found that particular digit. Keep probing the other digits with the negative lead and make a note of the pinout.

If you were lucky and found all 10 digits, the resistor (which goes to the + supply) is on the anode lead.

More likely, you will find a pin that glows in a strange shape with the negative lead. That's the anode. Move the resistor to this pin and then find the rest of the numeral cathodes.

Once you have the pins identified, you need to determine the cathode current. Unless the numerals are larger than 20mm or 0.8 inches  (lucky you if you found tubes that big !!!), the current will be less than 3mA. I'd use as small a current necessary to get a nice even glow, and then add about 10-20% to allow for aging.

[kay486]

You can easily identify the cathode in most of the tubes by looking near the base of the tube where the wires connect through glass. The anode ususly has some sort of insulation, tiny glass tube around the wire or some sort of ceramic coating. It has to be coated to prevent undesired glow on all the surounding cathodes.

[electrofish]

Thanks for you advice evreyone.  Much appreciated.
Haven't got my hands on them yet but soon : )
Regards
John