Electrical Measurement Instruments

The devices, methods, and calculations used to measure the electrical quantities in an electrical circuit is known as electrical measurements. Electrical measurements are commonly used to measure voltage, current, resistance, and power. It can measure a lot of other electrical quantities but these four are the most common.

Electrical measurement consists of a lot of methods to use a device or instruments to measure the electrical quantities. Electrical measurement to measure electrical quantities can be done by measuring the desired parameters in an electrical circuit.

Of course, measuring the parameters of an electrical circuit is possible with analog circuits and digital circuits. Mechanical parameters such as pressure, force, flow, temperature, and others can be converted into electric signals analysis.

More advanced electrical measurements are related to physical parameters such as electrons, light, and other uncommon examples for common people to measure.

The common electrical measurement, commonly involves:

• Electrical voltage
• Electrical current
• Electrical power
• Resistance
• Inductance
• Capacitance
• Impedance and reactance
• Phase
• Power gain
• Frequency
• Noise
• Total harmonic distortion
• And many more.

Electrical Measurement

Electrical measurement depends on the measurement units that exist in an electrical circuit along with their range, whether it is small (pico, nano, micro, etc) up to large (kilo, mega, giga, etc).

The most standard electrical measurement units used to analyze an electrical circuit are voltage (measured in Volt or V), current (measured in Ampere or A), and resistance or impedance (measured in Ohms or Ω).

The electrical measurement instruments measure the parameters based on the International Metric System, known as SI or International System of Units.

The seven SI base units, which are comprised of:

• Length – meter (m)
• Time – second (s)
• Amount of substance – mole (mol)
• Electric current – ampere (A)
• Temperature – kelvin (K)
• Luminous intensity – candela (cd)
• Mass – kilogram (kg)

For electrical related measurement, we can only find electric current. What about voltage, resistance, inductance, capacitance, and other parameters?

The SI system is a measurement system that can derive  an SI base unit into other commonly used electrical measurement units.

The most basic example of this is the triangle of Ohm’s Law.

Simply by finding the relationship of those three, it is easy to find the remaining desired values. This triangle is also found in the Power triangle.

Below is the most used measurement of electrical units.

Along with the relationship between parameters in the circuit, the base units also have multiplication to show the quantities are small or large.

It is a hassle to write a lot of 0 whether it is in front of the base number to show how small it is or behind it to show how large it is.

For example, we can simply write 1,000 V into 1 kV. This is much simpler and comfortable to read and write.

Below is the table of multiplication and the prefixes.

Electrical Measurements and Instrumentation

Electrical measurement instrumentation are the devices we used to measure various parameters found in an electrical circuit. Just as stated above, the basic measurement units are voltage, current, power, resistance or impedance.

Nowadays, almost every electronic measuring equipment is portable, small-sized, easy to carry, easy to use, and easy to buy. Even with this ease, they are still accurate and reliable.

Below are the few examples of electrical measurements and instrumentation:

• Voltmeter : measurement instrumentation to measure the potential difference between two points in a closed circuit.  We also use this mainly to measure a voltage of a battery, or a voltage of a power supply or our grid system. It is able to measure the voltage of a DC circuit and AC circuit. Voltmeter high very high resistance to prevent any power consumption that can alter the result.
• Ammeter : measurement instrumentation to measure electrical current flowing in the circuit. Ammeter has very low resistance to prevent the current being resisted. This instrument is also able to measure AC and DC current.
• Ohmmeter : measurement instrumentation to measure electrical resistance or impedance in a circuit.
• Wattmeter : measurement instrumentation to measure power in a specific point or circuit element by deriving the voltage and current measured on the same element.
• Multimeter : measurement instrumentation that is built to be able to measure a lot of electrical measurement in a single device such as voltage, current, resistance, power, capacitance, inductance, and many more.
• Oscilloscope : this is an advanced instrument that is able to deliver measurement in a digital graphical display electrical signals.

Filter circuits can also be used for measurement tools, but it is more advanced.

Types of Electrical Measurements

• Analog : analog instrumentation uses electromagnetic systems to move the pointer every time a current or voltage passes through between two points. The magnetic field is generated by this movement. Because it is an analog does not mean it is only suitable to use on an analog circuit.
• Digital : digital instrumentation such as digital multimeter has the same concept with analog meters but with a digital display but more accurate, faster, and reliable since we do not need to observe the scale and pointer. Just as above, it is not only used for a digital circuit.
• Register : this type of instrumentation is able to record the value, and can be either analog or digital. This measurement is presented in a graph just like an oscilloscope can do.

Frequently Asked Questions