# Need help with inductor on oscilloscope

Discussion in 'General Electronics Chat' started by Brandon, Dec 22, 2004.

1. ### Brandon Thread Starter Senior Member

Dec 14, 2004
306
0
Forgot how to connect up the oscilloscope to properly find the hysterisis curve for an inductor component.

I know I have to plot my X vs Y on the scope one of them being the Voltage across the Inductor to ground and I just don't remember the rest after that.

I am trying to find the point of saturation for a transformer I constructed and want to see at what frequency and voltage it beings to deviate from normaly operation.

2. ### bipin Well-Known Member

Mar 21, 2004
80
0
Hi,

For Plotting the hysteris curve what you need is to apply a triangular wave of the same frequency(for which the inductor is designed).

Put the oscilloscope in XY mode then apply the triangular voltage waveform to X-axis(CH1 )(and to the inductor as well) and the resultant current through the inductor to Y axis(CH2).
Adjust the volt/div of both the channel to get a proper shape of the curve.

To capture the current waveform you may use a low value resistor in series with the inductor and the corresponding drop can be taped.

If it is in the case of a transformer then you can load the transformer to 25% of its load and the out put voltage can be used insted of the current waveform. This is possible because the out put voltage is a result of the fulx formed and the flux is a result of the current through the primary and this current will have its own lagging behavior as it is through the primary inductance.

You can consider the graph as the BH curve with H in X axis and B in the Y axis.

Remember, this BH curve will not be in proper scale unless you feed the X-Y input according to the multiplication factor and channel voltage gain.

Have fun.