Hi, Assume that one has a pair of metal spheres, A and B, some distance apart. A is connected to, say, a small van der Graaf generator and B is connected to a voltmeter which is then connected to ground. I expect charge to be induced on sphere B. How would one calculate the voltage one would expect to measure on sphere B? Would it depend on the radius of sphere B? Actually thinking about it I guess I should connect sphere B to the ground first to let induced charges run onto it, disconnect it, and then measure its voltage relative to ground. Is that right? Basically, what is the best way to measure the strength of a static electric field electronically? A field-effect transistor maybe?