18

Might be super obvious, but I've not encountered one of whatever this little dude is before:

strangle little bulb-like thing

I figured some sort of vacuum tube, but no idea beyond that. The two poles aren't linked. Found inside a heating control panel. Help would be greatly appreciated!

Bob
  • 151
  • 1
  • 10
slothgirl
  • 181
  • 1
  • 3

3 Answers3

35

I think it is a neon lamp - possibly an NE-2. The "I3" designator on the PC board tends to confirm that - "I" would indicate "indicator".

Peter Bennett
  • 59,212
  • 1
  • 49
  • 132
13

Neon lamp or gas filled surge arrester. Not likely a mercury tilt switch, since:
a) PCB mounted mercury switches are far more rare than neons/arresters
b) This looks like a PCB from a CRT monitor where gas filled arresters are very commonly used
c) There is no mercury bead visible

Community
  • 1
rackandboneman
  • 3,105
  • 9
  • 13
3

On the right image you'll see there's some mercury at the bottom inside of the enclosure.

It is a mercury tilt sensor/switch.

enter image description here

Harry Svensson
  • 8,169
  • 3
  • 34
  • 53
  • 13
    That's just a weird reflection - I've given it a good eyeball and wiggled it about, definitely no mercury in there. Weird though, otherwise it looks identical to your pic. – slothgirl Feb 09 '18 at 00:08
  • 1
    I think that mercury you're seeing is a trick of the light. Looks more like a neon bulb to me. – brhans Feb 09 '18 at 00:10
  • @slothgirl Hmm, have you tilted it though? Otherwise it might be something else... oh well. – Harry Svensson Feb 09 '18 at 00:11
  • @brhans It sure looks like it, though it's a weird placement for it. – Harry Svensson Feb 09 '18 at 00:11
  • 6
    They're sometimes used as sorta surge protectors in power supplies - so not intended to be seen. – brhans Feb 09 '18 at 00:15
  • Ceramic heaters need a tilt sensor so they dont burn the carpet and the house. THey must have cut down the volume of mercury these days so its almost invisible (LOL). They certainly dont need a neon light. But a gas tube surge suppressor seems like overkill protection for a ceramic heater? when I see an MOV. But if it is , the fuse is must have. – Tony Stewart EE75 Feb 09 '18 at 00:21
  • 16
    In a mercury sensor – as shown in your picture – the contacts/wires are at one end of the tube, allowing the mercury to sit at the other end (in normal orientation). In the OP's picture, the contacts/wires go almost to the end of the tube (and the leads where they enter don't appear insulated). If it were a mercury switch, the mercury would be completing the circuit (virtually) all the time. Screams neon to me. – TripeHound Feb 09 '18 at 08:08
  • 2
    It's not a weird reflection and it's not mercury. It's part of the base of the fuseholder, behind the lamp, in that shot. – Brock Adams Feb 09 '18 at 21:12
  • 2
    If it was a switch of any sort the circuit designation would start with "S" or even "SW", not "I"! It's an indicator. Hence, a lamp. Maybe used as a surge suppressor, as others have said. – Jamie Hanrahan Feb 09 '18 at 22:23