The resistance of an ideal ammeter is zero .
Voltmeter
A voltmeter is a high resistance galvanometer used for measuring the potential difference between two points . It is always connected in parallel .
The resistance of an ideal voltmeter is infinity . Conversion of a Galvanometer into a Voltmeter
A galvanometer can be converted into a voltmeter by connecting a high resistance into its series .
If a galvanometer of resistance G show full scale deflection for current Ig then required high resistance R , connected in series for converting it into a voltmeter of range V is given by