Ammeters and Voltmeters

1. May 15, 2010

MaXiiMo

Ok now this might be considered a dumb question for some but I'm really weak concerning electricity and I'm doing AS physics.
Now why are Ammeters connected in series in a circuit and do they have any resistance? I read that they "short" circuit the component. What does short circuit the component mean ?
What about voltmeters? Do they contain any resistance and why are they connected in parallel?

2. May 15, 2010

Redbelly98

Staff Emeritus
Elements in series will have the same current, so an ammeter in series with another element will tell you the current going through that element.
They do have resistance, but it is usually small enough to neglect. My own ammeter has a resistance that depends on the scale; it is 0.35Ω on the Amp scale, 2.4Ω on mA scale, and 100Ω on the μA scale.
It would mean to place a wire or zero-resistance in parallel with the component. Since the ammeter is in series, it does not short the component.
Elements in parallel will have the same voltage, so a voltmeter in parallel with another component will read the same voltage as is across that component. The do have a relatively high resistance, for mine it is 10 MΩ.

Hope that helps.