The instruments which are used to measure the power factors in any quantity are known as measuring instruments. Which are useful for measuring electrical quantities or parameters. The electric current cannot be detected by the eye. Electronic measuring instruments are used to measure the flow of electricity. These tools are important for understanding the nature and voltage of electric charges flowing in any electronic device.

Electronic measuring instruments are widely used to measure the amount of electric charge and the amount of electricity flowing through various electronic devices. Because different instruments involve different types of electric current and to measure current, voltage, and resistance, different types of electronic measuring instruments are designed and calibrated for different electronic devices.

**Voltage Measuring Instrument Voltmeter**

The unit of voltage is volt and the device or instrument with which the amount of voltage is measured is called a voltmeter. A voltmeter is used to measure the suitable voltage at any two points in an electric circuit., typically in volts, millivolts (0.001 volts), or kilovolts (1,000 volts). There are two types of voltmeters,

**DC Voltmeter:**It measures the DC voltage at any two points in an electric circuit and the peak value of DC voltage. DC voltmeter does not use a rectifier before the multistage amplifier.**AC Voltmeter:**It measures the AC voltage at any two points of an electric circuit and the RMS value of the AC voltage.

Many voltmeters are **digital**, displaying the reading as a numerical display. By moving a pointer indicating voltage on a scale, the instruments just described can provide readings in analog form, but digital voltmeters have higher accuracy than analog instruments.

**Current Measuring Instrument Ammeter**

The unit of current is ampere and the device or instrument with which the amount of current is measured is called an ammeter. An ammeter is used to measure the current flowing between any two points in an electric circuit. This device has an internal resistance of ‘0’, but has some amount of internal resistance. The measurement range of this instrument mainly depends on the resistance value. There are two types of ammeters,

**DC ammeter:**It measures the DC current flowing through any two points of an electric circuit.**AC ammeter:**It measures AC current flowing through any two points of an electric circuit.

**Resistance Measuring Instruments Ohmmeter**

The meter which is used to measure the resistance and continuity of an electric circuit and its components such as a meter is called an **ohmmeter**. It measures resistance in ohms. Resistor with low resistance is measured by **micro-ohmmeter** and resistor with high resistance is measured by **mega ohmmeter**. It is very convenient to use an ohmmeter but the measured value obtained is** less accurate**.

The ohmmeter provides an approximate value of the resistance. This is a very portable device. Its three types are series ohmmeter, shunt ohmmeter and multi-range ohmmeter.

**Series Ohmmeter**

The series ohmmeter is used to measure the resistance of a suitable resistor in a circuit whose value is unknown and to find the value of the unknown resistor by connecting that resistor in series with the ohmmeter. It is useful for measuring high values of resistors.

**Shunt Ohmmeter**

In shunt type ohmmeter, the resistor whose value is unknown and which is to be measured is connected in parallel (shunt) with the ohmmeter. It is useful for measuring low values of resistors.

**Multi-Range Ohmmeter**

The scope of this type of ohmmeter is very large. The meter has an adjuster, which can be selected according to the requirement and by setting a limit, the unknown value of the resistors can be known.

**Multiple Electric Function Measuring Instrument Multimeter**

A multimeter is an electronic device used to measure the quantities of voltage, current and resistance in an electronic circuit at a time or the value of a suitable component. It can be used to measure DC and AC voltages, DC and AC currents, multiple ranges of resistors, frequencies, etc. There are two types of Multimeter,

**Analog Multimeter:**Analog multimeters are instruments for displaying multifunction electrical measurements with indications by means of an arrow (analog) scale.

**Digital Multimeter:**Digital multimeter is a device for displaying multifunction electrical measurement with indication through digits.

**Symbols and Functions of Digital Multimeter**

Multimeters can be used to measure various high resistance, low resistance, DC voltage, AC voltage, DC current and AC currents.