Which instrument is used to measure electric current?

An ammeter is a measuring instrument specifically designed to measure electric current in a circuit. Because electric current is measured in units called amperes (or "amps"), the meter is naturally called an "ammeter." To help remember the other instruments: a voltmeter measures voltage (electromotive force or potential difference), and an ohmmeter measures resistance (in ohms). An electrometer is a highly sensitive instrument used to measure electrical charge or tiny potential differences, but not standard circuit current. When using an ammeter, you must place it in series with the circuit so that the current you want to measure flows directly through the device.