What is this and what does it do?

[Bonnewagon]

My handy dandy 25 year old 12 volt test light blew a bulb. OK, easy enough, I swapped 12 volt bulbs and was on my way. But then I noticed that the big spring with the neon looking thing at the end never lit up. What is it and why is it there? The regular12 volt bulb is screwed into the handle and connected to the alligator clip wire. That makes sense but the neon thingy does not. It is not part of a circuit. Anyone know what it does?

 

[DRIVEN]

Hydroscillator.

 

[Bonnewagon]

Define that?

 

[ELCAM]

It should light up in pulses when touching a hot spark plug wire. No need for the red wire to be hooked up, you are the ground holding the case, it wont shock you. Works like static electricity.

 

[DRIVEN]

Define that?

Urban Dictionary: hydroscillator

None

www.urbandictionary.com

 

[Bonnewagon]

Mortimer Ford? No wonder I never knew what it was. Thanks ELCAM, that makes sense. I will have to try that out. So I had a spark tester in my hands the last 25 years and didn't know it?