What meter used to measure electrons/current?

Question

which is used to measure:

flow rate of electrons

energy per charge

which meter has largest resistance and why (voltmeter or ammeter)

What affect would an ammeter have on a circuit if it's resistance was 100 times greater than any of the lights in the circuit?

thank you

Answer 1

Meter used to measure current (flow of electrons) is nothing but ammeter.

No meter measure energy per charge directly. We have to calculate manually by means of equations.

Voltmeter & ammeter both have been used for different purposes. But one common point is both should not affect actual circuit when they are connected in circuits for measurement. It means a voltmeter doesn't consume current (very little fraction is allowed). Similarly an ammeter doesn't consume voltage very little fraction is allowed).

In order to acheive this, always voltmeters are mannufactured with very high resistances so that current thru it is very much small or negligible. similarly ammmters are mannufactured with very low resistances so that voltage across it is very much small or negligible.

Since ammeter is connected in series with the circuit (here lights), when its resistance is 100 times of lights then current will be reduced to 101 times of its old value(without ammeter).I hope you can understand this 101 times... :-)          But this will not be possible in practical. In actual, the resistance will be in the order of milli ohms.

Answer 2

1. Ammeter

2. voltmeter

3. voltmeter has highest resistance.  If it were infinite (highest possible), then it would not take any current from the circuit it was measuring, and cause no disturbance.

4. 100 times less current would flow (and the lights would probably not light-up).

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