# Step Up Transformer Vs Step Down Transformer | Difference between Step Up Transformer and Step Down Transformer

This page on compares Step Up Transformer vs Step Down Transformer describes difference between Step Up Transformer and Step Down Transformer with circuit diagrams and equations.

## What is Transformer and How it works

Definition:
The transformer is a electric device which converts an alternating current (AC) of certain voltage to an AC of different voltage (either more or less).

Following two principles are used in a transformer.
• When fluctuating current flows through wire it generates magnetic field.
• When magnetic field fluctuates around any piece of wire, it generates electric current in wire.

In a transformer two coils are placed side by side and fluctauating or alternating current is applied to the first coil. Hence as a result current is generated in the second coil. This is known as electromagnetic induction. In order to have efficient energy transfer between the two coils viz. primary and secondary they are wrapped around soft iron bar known as core.

If the number of turns in both primary and secondary coils are same, same amount of current is produced in the secondary coil as the primary coil.
Refer Transformer basics and types >>.

If the number of turns in the secondary coil are more or less compare to number of turns in the primary coil, we can obtain step up transformer and step down transformer respectively.

## Step Up Transformer

If the secondary coil has more turns compare to primary coil, it is called Step Up Transformer. Here secondary voltage is higher than the primary voltage and secondary current is smaller than the primary current. Figure-1 depicts circuit of Step Up Transformer.

## Step Down Transformer

If the secondary coil has less turns compare to primary coil, it is called Step Down Transformer. Here secondary voltage is smaller than the primary voltage. Figure-2 depicts circuit of Step Down Transformer.

Vs/Vp = Ns/Np ... Equation-1
Is/Ip = Np/Ns ... Equation-2
Where,
Vs = Secondary Voltage, Vp = Primary Voltage
Ns = Number of turns in secondary, Np = Number of turns in primary coil
Is = Secondary current, Ip = Primary Current