What is a transformer?

What is Transformer and How to work Transformer? A transformer is a static device that transforms the electrical power from one circuit to another without changing frequency. Commonly, it is used to step up or step down voltage levels between circuits.


We need to know the power system before understanding the Transformer.

Power System:


  • Firstly, Produce 11kv power from the generating station in the AC system.
  • Transmit this voltage to 230kv/400kv using a step-up transformer. The main reason for high voltage transmission is reducing R Loss.
  • The Next-Step step-down the voltage to 230v/400v use it the consumer


Mainly, the transformer is used to increasing or decreasing the voltage

Working Principle of Transformer:

The basic principle on which the transformer works is Faraday’s Law of Electromagnetic Induction or mutual induction between the 2 coils. The working of the transformer is explained below. The transformer consists of two separate windings placed over the laminated silicon steel core.

What is Transformer and How to work Transformer, you also learn about TROUBLESHOOTING CONTROL LOOP?

The winding to which AC supply is connected is called primary coil and to which load is connected is called secondary coil as shown within the figure below. It works on the AC only because an alternating flux is required for mutual induction between the 2 windings.

supply power

When the AC supply is given to the first winding with a voltage of V1, an alternating flux ϕ sets up within the core of the transformer, which links with the secondary coil and as a result of it, an emf is induced in it called Mutually Induced emf. The direction of this induced emf is opposite to the applied voltage V1, this is often due to Lenz’s law shown within the figure below

Physically, there’s no electrical connection between the 2 windings, but they’re magnetically connected. Therefore, the electric power is transferred from the first circuit to the secondary circuit through the coefficient of mutual induction.

The induced emf within the primary and secondary windings depends upon the speed of change of flux linkage that’s (N dϕ/dt).

dϕ/dt is that the change of flux and is that the same for both the first and secondary windings. The induced emf E1 within the primary coil is proportional to the amount of turns N1 of the first windings (E1 ∞ N1). Similarly, induced emf within the secondary coil is proportional to the amount of activates the secondary side. (E2 ∞ N2).

How to make a transformer:

Most of us don’t know how to make a transformer. Let’s learn how to make a transformer with today’s discussion.

Assumed we will build a power transformer of 50 volts 2 amp or 100 VA quality, so we have to choose our core first. Core Selection Formula: A= √P / 5.58 (A=Core Size, Inch P= Transformer Power, VA). A= √ 100/5.58 = 1.792 or 1.8 square inch. This calculation can also be done in centimeters, then the formula will change.

We got our desired core size. Let’s give wire patches to the core, but how many patches will I give. Here’s another clue: TPV= 10 ^ 8 /(4.44 * B * A * F), here TPV means Turn Per Volt i.e. number of patches per volt, B is magnetic flux which generally holds 60000, but it changes based on core and frequency, A is core area and F is frequency.

TPV= 10 ^ 8 /(4.44*60000*1.8*50)= 4.17, that means 4.17 patches for every 1 volt.

Let’s put a wire patch in the core. 220*4.17 = 917.4 or 918 patches for 220 volts on the primary side. And 50*4.17 = 208.5 or 209 patches for the secondary side.

Let’s choose her, Primary side current (100/220) = 0.454 amp and secondary side current (100/50) = 2 amp. This time we will be able to find the power of 0.454 amp and 2 amp from the SWG or AWG chart and give 918 patches for the primary side and 209 patches for the secondary sites. You will get different quality voltage by taking out multiple terminals in this way. After this, our desired transformer will be made if you block the core and burn it in the wire bobbin.

We should take care that the primary and secondary sides are not short, so after the one side obstruction, we should wrap the insulation paper. Then to do the next side congrats. Also need to tighten the cores. If there is a gap in the core, the transformer will shake and it will make noise.

Blocking the transformer in this method can lead to some simple problems initially which can be solved with a little headache.

I have said a lot with my little knowledge. I request you to correct me if there is any mistake. Thank you for hardly reading the whole thing.

How to make transformer