what is the difference between ammeter and voltmeter.

ammeter is used to measure the amout of current in the circuit...and voltmeter is used to measure the potential difference in a circuit

ammeter  -  shows  the reading of theof current present in an circuit.

voltmeter  -  shows the reading of the  of  voltage  present in a circuit.

An Ammeter connects a low impedance on the test points, so the equivalent of that is a "short circuit" between the test points. This is done to avoid a drop of current on the tested circuit.

A Voltmeter connects a high impedance on the test points, so the equivalent of that is a "open circuit" between the test points. This is done to avoid a drop of voltage on the tested circuit.

Difference Between Voltmeter and Ammeter

When exploring the difference between two electronic instruments, there are two main points of distinction which are their functionality and internal circuitry. Let us compare voltmeters and ammeters according to these two main features.

Voltmeter Vs Ammeter: Functionality
The obvious difference between a voltmeter and ammeter is that the former is used to make an accurate measurement of potential difference, while the latter is used to measure current flowing between two points. They differ in functionality but they measure two aspects of an electrical measurement which are voltage and amperage. Nowadays, multimeter instruments are available that do the job of a voltmeter and an ammeter.

Voltmeter Vs Ammeter: Connection
There is a difference between how a voltmeter and an ammeter are connected in a circuit. When measuring the voltage across a resistor or a conductor element, the voltmeter is always connected in parallel. As opposed to this, to measure the current flowing through a circuit element an ammeter should be connected in series.