What are Voltage, Current, Power, and Other Electrical Terms?

Electrical Engineering basics are important to read and understand the technical terms. No matter what type of technology we are using, these terms help us analyze the hardware of the system.

For example, if a battery has a 6000 mAh capacity. We raise a question about the battery capacity.

What is meant by mAh?

The term mAh refers to the milliAmps Hour, which means 1/1000th of an Amp Hour. One ampere is equal to 1000 mAh. Ampere is the unit of current and so the term ‘mAh’ is used to represent the capacity of a mobile battery in the current.

Like this, the battery has a 5V input, which means the battery needs 5 volts of voltage as the input.

There are so many electrical terms like this. But we want the basics. Let’s discuss these terms briefly. So, you can understand the hardware stuff on this website. Here I can provide the most commonly used terms of electrical engineering.

Basic Electrical terms:

  1. Voltage
  2. Current
  3. Resistor
  4. Inductor
  5. Capacitor
  6. Power
  7. Frequency
  8. Conductor
  9. Insulator
  10. Circuit and Network



Voltage is nothing but the potential difference between the two points in an electrical component. Then the component is called the Electrical source or Voltage source. ‘V’ is the symbol that represents the voltage, and ‘volts’ are the units.

Ohm’s law is the basic principle of Electrical Engineering.

According to Ohm’s law, voltage is equal to the product of current and resistance.

Voltage = Current * Resistance (V = IR)

What is current?

A current is nothing but the transmission of energy by the electrons. The transmission may occur in between unique sources. Back in the 1880s, Thomas Edison was the first person who discovered Direct Current (DC) for the first time with his experimental invention of the bulb.

The people in the 19th century were feeling well with the DC power by the Thomas Edison company. Instead of no current, the DC power is the best option.

But people like Nikola Tesla know that there are so many problems with the DC supply. So, they found a new type of current conveniently that can pass in all directions. Hence, the origin of the Alternating Current happened.

William Stanley Jr. makes the first move in the invention of Alternating Current (AC) with his design called an ‘induction coil’. After that, the AC was developed by George Westinghouse in 1886. Yet, there are some problems with their protocols and it was overcome with the invention of the ‘induction motor’ by Galileo Ferraris and Nikola Tesla.

If you are enthusiastic about the history of the current, I recommend you to watch the movie ‘War of currents’. The movie will give an outstanding experience with significant information.  

According to Ohm’s law, the current is equal to the ratio of voltage to the resistance.

Current  = Voltage / Resistance (I = V / R)


The resistor is an element that can resist or control the flow of current (I) in a circuit. The resistance is denoted with the letter (R) and measured in Ohms. According to Ohm’s law, Resistance is equal to the ratio of Voltage to the Current.

Resistor = Voltage / Current (R = V / I)


We can simply say that the copper coil is an inductor. An inductor is an element that can store energy in the form of an electromagnetic field. The inductor is represented with the letter ‘L’ and the inductance is measured in Henry.

The inductor doesn’t allow sudden changes in current.


A capacitor is an element that is used to store energy in the form of an electrostatic field. The capacitor is represented with the letter ‘C’ and we measure the capacitance in Farad.

The capacitor doesn’t allow sudden changes in voltage.

Generally, we use capacitors in motors, motherboards, tube lights, Power transmission, etc.


The power of a system is defined as the product of its voltage and current. It is represented with the letter ‘P’ and is measured in watts.

All the electronic devices we are using must consume power. Some are low and some are high, but consumption is common.


If a particular thing or a substance occurs repeatedly in a particular period of time, then the phenomenon is called a frequency. We measure the frequency in Hertz (Hz).

Here the voltage is the main thing, and we need to know the frequency of it.

It is compulsory to maintain the frequency level constant in order to avoid damage to household electronic devices.

We use 50 to 60Hz frequency power systems in our country, India.


The conductor is an element that has zero resistance. So, we can use this element to transmit electrical energy from one place to another. Based on the distance of transmitting energy, different types of conductors are used.

From a simple copper wire to the overhead HVDC transmission lines, all the cables we are using are coming under this conductors category.


An Insulator is a thing that has infinite resistance, which means the current isn’t able to pass through it. High voltage conductors need high-level insulators to control the current.

Some insulators around us:

  • Rubber
  • Bakelite
  • Ceramic
  • Glass
  • Wood

Circuit & Network-

The circuit is a type of loop connection, which means the current must pass through all the elements in the circuit or connection. If a connection is not in a loop, then it is not a circuit anymore.

A network is a connection that contains both active and passive elements. Voltage and current sources come under active elements and Resistance, Inductance, and capacitance are coming under passive elements.

There is no need to use the connection as a loop. And there is no need to pass the current in all elements in the network.

All the circuits are networks, but not all the networks are circuits.

These are the most popular and common terms we are using in the hardware study and play a key role in hardware analysis. If I miss any of the popular terms, let me know with your comment.