1. An instrument used to measure differences of electric potential, commonly called voltage, in volts or units that are multiples or fractions of volts.
2. A tool that measures electrical voltage; for example, the potential difference between two points.
3. A device; such as, a galvanometer, that measures in volts the differences in potential between different points of an electrical circuit.
3. A device that measures voltages of either direct or alternating electric current on a scale usually graduated in volts; such as, millivolts or kilovolts.

The typical commercial or laboratory standard voltmeter currently in use probably employs an electromechanical mechanism in which current flowing through turns of wire is translated into the reading of the voltage.

Another type of voltmeter includes uses electrostatic fores and is the only voltmeter to measure voltage directly instead of by the effect of current.

1. A voltmeter consisting of a direct-current milliammeter calibrated in volts and connected to an amplifier-rectifier circuit.
2. A device that measures voltage in amplifier-rectifier circuits.

1. The voltmeter whose sensitivity is increased by amplification.
2. A voltmeter that uses the rectifying and amplifying properties of electron devices and their associated circuits to secure desired characteristics; such as, high-input impedance, wide-frequency range, crest indications, peak-to-peak indications, and so on.

It is called a "vacuum-tube voltmeter" when its electron devices are vacuum tubes.

1. An instrument that measures voltage according to the degree of attraction or repulsion between charged bodies.
2. A voltmeter which works by measuring the force exerted between stationary electric charges which is usually graduated in volts or kilovolts.
3. A voltmeter in which the voltage to be measured is applied between fixed and movable metal vanes.

The resulting electrostatic force deflects or turns the movable vane against the tension of a spring.

1. An electrothermal ammeter (instrument for measuring an electric current in amperes or basic units of electric current) employing a series resistor as a multiplier, and so measuring voltage instead of current.
2. An instrument which measures voltage and operates as an electrothermal ammeter, using a series resistor as a multiplier.

An instrument designed to measure high voltages by determining the distance between two metal spheres at which a spark will jump.