ID-a-gadget

[California]

Bingo!

It tests the spark from a magneto, or coil. If the screw has to nearly touch the end of the brass rod, the spark is weak. The spark is observed inside the glass tube to make it idiot-proof.

Here's the present day version.

(Source) "Instructions: Plug into coil to measure jump of spark from 0 to 40,000 Volts."

And here's the general idea of how it works.

(Source)

What did I win?

 

[winston1]

Those old timers were sharp cookies. California, so are you. :thumbsup:

 

[deepNdirt]

Makes perfect since:thumbsup: But why with having the sharpened spike point? instead of a blunt end that would insert into the coil etc,etc,
I have several of the light testers that you jab the spike point in through the wires insulated shielding to test for continuity,
Though this device doesn't have a bulb that would light up... a spark inside the glass tube makes good since, the screw can be adjusted not to contact the probe at any increment,
California you have won the ( Old timers Einstein Award )

 

[Car Doc]

Good job California I learn something new on here everyday!