Interesting facts about antique electrical measuring instruments

[mathlete]

I wasn't sure where to put this thread... if it's in the wrong place, please move it.

Anyways, I'm making a couple of posters for display and one of the showcases is featuing antique equipment like ohmmeters (Wheatstone bridge), ammeters, voltmeters, etc. I was wondering if anyone knew of any cool/quirky/interesting little facts about anything related to this subject that I could put into the poster? Almost anything will do. I just don't want to bore people by putting only V=IR stuff and how the innards work.

 

[GENIERE]

II was wondering if anyone knew of any cool/quirky/interesting little facts about anything related to this subject that I could put into the poster? Almost anything will do. I just don't want to bore people by putting only V=IR stuff and how the innards work.

Throw in the "string galvanometer" invented by Einthoven. A very sensitive meter movement using a mirror in place of the indicator needle. Used in the beginning of the last century to do ECG exams as electronic amplification was not possible.

 

[Integral]

Throw in the "string galvanometer" invented by Einthoven. A very sensitive meter movement using a mirror in place of the indicator needle. Used in the beginning of the last century to do ECG exams as electronic amplification was not possible.

This sounds like what we called a "Ballistic Galvanometer"

 

[Meir Achuz]

I'm an oldtimer who used both of those in my UG lab course.
The only difference for the ballistic galvonometer was that it had a large moment of inertia so it didin't move appreciably until the charge from a discharging capacitor had passed through.
What about the experiment of measuring with g using a microscope and a stop watch?

 

[inha]

Here's an anecdote based on real life: Nothing ever works. Especially if the particular device hasn't been used recently.