Science Buddies: "Ask an Expert"

Hi, I am doing the experiment invloving Wimshurst machine. I was trying to measure the voltage by using moving coil volt meter but the result shown was less than a volt. I did several times with several voltmeter but the result was the same. so i was wondering is there any device which allow me to measure to voltage of the sprak?

suangchanok - It is impossible to measure a static electricity charge with a conventional moving coil voltmeter as they would require around 100 microamps of current to move the coil. Even digital, vacuum tube or FET input voltmeters would require a current much higher than the Wimshurst machine can produce. You need a sensitive instrument like and electroscope or electrostatic voltmeter. You won't find these in your standard electronics stores, but here is a link to a YouTube video of a DIY instrument you might consider. To calibrate if, you would use a known high voltage from some other source to assist.

https://www.youtube.com/watch?v=wxIxVaoFsX8

Rick Marz

thanks for your help, that's help a lot

btw according to the youtube link, i thought that i would build one myself but i google search it but nothing came up so how do i actually make this and what exactly do i need?