Graphs of Current through a Transformer

AI Thread Summary
A user created a makeshift transformer with a circular core and wire, questioning the sharp spike in the induced current when a 220 V AC current is applied. The input current displays a perfect sine wave, while the induced current shows unexpected spikes, leading to speculation about the magnetic field's behavior during current direction changes. Responses indicate that the observed waveform suggests core saturation, resulting in high magnetizing current and harmonics. Safety concerns are emphasized, warning against experimenting with 220 V AC mains without proper supervision. The discussion is locked due to the dangerous nature of the topic, encouraging safe exploration of electrical concepts.
lekh2003
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I have created a make-shift transformer using a circular core and some wire:
4efe9cf1-0016-4fe4-bac0-b0da846b6f48.jpg


It is quite basic, but I have some questions about the currents induced when one side of this transformer has a 220 V AC current passed through it.

I have an oscilloscope from which I have the graph:

41343cfc-2ce1-4acc-a93f-635bee6f3368.jpg

The perfect sine wave is the input current (220 V). I am just wondering why the induced current (the other side of the transformer) has such a sharp spike in the current. My initial prediction was that the induced current would also be a sine wave.

Then, when I saw the spike, I thought that there was a spike because the magnetic field is changing most when the current completely changes direction (When the sine wave intersects with x-axis). Am I right?
 

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What did you connect across the secondary (i.e. the other side of the transformer)?
 
Directly to the oscilloscope to check the voltage going through.
 
lekh2003 said:
Directly to the oscilloscope to check the voltage going through.
You are actually measuring voltages here. The sinusoidal waveform is your mains voltage. From the secondary voltage graph (the spikey waveform), it appears that the core flux is flat-topped with a lot of harmonics.
If the core flux is flat-topped, the core is saturated and is drawing very high magnetizing current.

Check the resistance of the primary coil.
 
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@lekh2003, your profile says you are only 14. I believe it is very dangerous for you to be trying anything on 220V ac mains.
Be very careful and do everything under proper supervision.
 
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The thread will remain locked.

PF does not allow public discussion of dangerous topics. Playing with 220V mains voltage certainly qualifies as dangerous. The OP is encouraged to continue his curiosity, but to choose his experiments with safety foremost.
 
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