# Difference between CT and PT

In this article we will learn about the difference between CT and PT. We will also learn about the current transformer and potential transformer. We will know about what is basic difference between CT and PT.
These are some basic difference between CT and PT

### Current transformer (C.T.)

The current transformer is a step-up transformer which is used to steps down the current to a known ratio. Its primary consists of one or more turns of thick wire in the series with the line. The secondary consists of a large number of turns of fine wire and provides for the measuring instruments and relays a current which is a constant fraction of the current in the line. It is used for measure high current. Which means it is used as current measuring instrument… as like 100/5A rating current transformer.

### Potential transformer.

It is also a step down transformer and steps down the voltage to a known ratio. Its primary consists of a large number of turns of fine wire connected across the line. As like 11KV/110V potential transformer.

## Difference between CT and PT

 CT (Current Transformer) PT ( Potential Transformer ) 1. It is connected in series with the power circuit. Which means CT is always connect in series with power circuit. It is connected in parallel with the power circuit. so it is main difference between ct and pt. 2.  its secondary is connected to Ammeter Its Secondary is connected to Voltmeter 3. Its secondary work always in short circuit condition. Its secondary work always in open circuit condition so these are also a basic difference between ct and pt. 4. CT primary current depend on power circuit current. Its change according to power circuit current. PT primary current depend on Secondary burden. According to secondary turn its change. 5. CT primary current and excitation vary over wide range with change of power circuit current. PT primary current and excitation are restricted to a small range. 6. In this transformer one terminal of secondary is earthed to avoid the insulation break down. In this transformer one terminal of secondary can be earthed for safety. not compulsory 7. Its secondary never be open circuited. Which means its cannot be open. Its secondary can be open. Or we can used its in case of open circuit condition.
Hence it is the basic difference between CT and PT. if you will find any incorrect above please comment below in comment box.

For knowing more about the difference between CT and PT you must watch this video.