Voltage, Current, Power and Resistance are terms that are not limited engineering nowadays and has become a part of our normal day-to-day vocabulary instead. But there are times when even experienced professionals tend to get confused about the relation and conversions between these Electrical measurements. The objective of this blog is to act as a primer for the beginner as well as a quick revision for a professional in understanding these electrical units, their functions and their relations.

What is Electricity?

Electricity simply can be defined as the effect of an electric Charge. It can be static in form of stored charges (for ex-battery) or flowing through conductors (wires or cables) also commonly known as Electric Current.

Static Charge
Flowing Charge

What is Current then?

Current is the rate at which the charged particles or more precisely, electrons are flowing through the conductor. Simply put, it is the measurement of the quantity of electrons flowing through the conductor.

Current Direction

The diagram given above helps us to understand this concept better… when there is a small quantity of electron flow, it is called a small current flow and vice-versa. Amperes is the unit of measurement for current.

How is Voltage connected to this then?

Voltage is the pressure of movement of charge across the conductor. Simply put, higher voltage translates to a higher push for particles to travel through the conductor which translates to a higher magnitude of current.

Voltage works on the principle of potential difference therefore, it travels from a region of higher potential to lower potential.  A higher potential can be simply described as a region having a higher number of charged particles. It can be compared to the flow of water in pipes as water also flows from a region of higher to lower density.

High pressure

So, it can be said in short that voltage and current work together making a circuit function properly. Voltage is measured in Volts(V).

Where does Resistance come into play then?

Resistance, as the name suggests, resists the flow of current. This happens because even conductors in real world do not have ideal properties and atomic structures. This makes them prone to resisting the flow of electrons through them.


This property of materials can in turn be utilized to control the amount of current flow according to requirement. Resistor is a device used to implement control. It is measured in Ohms.

So, what is Electric Power then?

Electrical power is the rate of transfer of electric energy by a circuit per unit time. Basically, electricity is consumed by a circuit in 1 unit of time, therefore, unit of time is considered to be hour usually. The electricity consumed is calculated by multiplying voltage with current. The unit of Electric power is Watts (w) which is also considered a product of Ampere (A) and Volt(V).

The Final conclusion

In conclusion, the easiest way to understand workings of electricity is to simply compare it to the flow of water in a simple plumbing system.

What about the relationship between these then?


These two triangles namely the POWER TRIANGLE and the OHM’S LAW TRIANGLE can easily relate the quantities together in a organized manner.