# Measuring Current using Current transformer

#### Qual

Joined Aug 5, 2016
48
Hi ,

i was trying measure current using Current Transformer but i see spikes at the output of transformer and cant see proper waveform on oscilloscope.

Attached is the waveform...

Any suggestion.

I want feed the voltage to Micro controller so that i can display same on LCD.

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#### DickCappels

Joined Aug 21, 2008
9,347
That waveform is normal for some types of loads, especially capacitor input filters.

What is the source (AC power line?) and load (input to a power supply or electronic appliance?) for the circuit you are measuring?

#### Qual

Joined Aug 5, 2016
48
Source is AC power line and load right now using a rheostat..! ( 56 ohms)

#### AlbertHall

Joined Jun 4, 2014
12,161
The section at the top of the display seems to be showing a sine wave though:

#### DickCappels

Joined Aug 21, 2008
9,347
I am going to take a guess: You are not using a transformer that was designed to measure current or you do not have an adequate shunt. What kind of transformer are you using? What are you using for a shunt? (Shunt: The resistor across the primary that sets the scale)

#### Qual

Joined Aug 5, 2016
48
I am going to take a guess: You are not using a transformer that was designed to measure current or you do not have an adequate shunt. What kind of transformer are you using? What are you using for a shunt? (Shunt: The resistor across the primary that sets the scale)

i am using 56100C current transformer from Murata for measuring current.

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#### AlbertHall

Joined Jun 4, 2014
12,161
You are way outside the frequency range of that transformer. From the datasheet:
 20kHz-200kHz frequency range

#### Qual

Joined Aug 5, 2016
48
You are way outside the frequency range of that transformer. From the datasheet:
 20kHz-200kHz frequency range

so i won't be able to measure current ?!! so is that transformer used is wrong ??

any help pls...

#### AlbertHall

Joined Jun 4, 2014
12,161
You cannot use that transformer to measure current at 50Hz. It is intended for switched mode supplies and the like.

Joined Jul 18, 2013
26,004
What kind of current are you measuring, would a ACS712 work for you, although they are in circuit type rather than transformer, comes with isolation build in.
The can be had for a couple of $'s on ebay with circuit, 5A, 20A and 30amp ranges. Max. Thread Starter #### Qual Joined Aug 5, 2016 48 What kind of current are you measuring, would a ACS712 work for you, although they are in circuit type rather than transformer, comes with isolation build in. The can be had for a couple of$'s on ebay with circuit, 5A, 20A and 30amp ranges.
Max.

i want to measure the AC and DC current. Want to build my own circuit.... so this attempt