31 May 2020

Difference between Step-up and Step-down transformer

The main key difference between step-up and step down transformers is, the step-up transformer raises the output voltage whereas the step-down transformer reduces the output current. Here this article gives information about the main key difference between step up and steps down transformer are listed below.

Definition of a step-down transformer:


A step-down transformer reduces the output voltage or in other words, converts high voltage, low current power into voltage, high current power. Our power circuit carries voltage from 230-110 v but the doorbell requires only 16v. Therefore the step-down transformer should be used to reduce the voltage from around 110v or the voltage from 220v to 16v. 

Definition of step-up transformer:


When the voltage is raised on the output side, That time the transformer is called the step-up transformer. In this transformer, the number of turns in the secondary winding is always greater than the turns in the primary winding because a high voltage is developed on the secondary side of a transformer. 

The main key difference between step-up and step-down transformers are listed below:

  • In Step-up transformer, the low voltage winding is the primary winding and the high voltage winding is the secondary winding, while in a step-down transformer, the low voltage winding is the secondary winding.
  • When the output voltage is greater than its input voltage, it is called a step-up transformer, while the step-down transformer output voltage is less. 
  • The step-up transformer extends the voltage from 220v-11kv or above, whereas the step-down transformer has the voltage from 440-220v, 220-110v or 110-24v, 20v, 10v etc. 
  • In a step-up transformer, high voltage winding is the secondary winding, while in a step-down transformer high voltage winding is the primary winding.
  • In a step-up current is low on the secondary winding, while in a step-down transformer, the current is high on the secondary winding. 
  • Step-up transformers are mainly used in power plant, x-ray, machine, microwave, etc while step-down transformer is mainly used in doorbell, voltage converter, etc. 
  • In a step-up transformer, the primary winding is made up of thick insulated copper wire and the secondary is made up of thin insulated copper wire while in a step-down transformer, the output current is high so the thick insulated copper wire is used for making secondary winding. 
  • In a step-up transformer, the current and magnetic field is less developed in the secondary winding, and it is highly developed in the primary wiring. but in a step-down transformer voltage is low on the secondary end thus the current and magnetic field is high.
Explore more information:
  1. Difference between star delta connection
  2. Difference between a power transformer and distribution transformer 

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