5244B - Channel A and Channel B not equal

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Moonwalker
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5244B - Channel A and Channel B not equal

Post by Moonwalker » Fri Oct 16, 2015 11:18 pm

I've been measuring a signal from a buck converter and noticed that channel A and channel B are not showing exactly the same signal. Channel B is showing a larger ripple than channel A. See file attached.
Any help?
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Martyn
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Re: 5244B - Channel A and Channel B not equal

Post by Martyn » Mon Oct 19, 2015 7:22 am

If you swap the probes around do the differences stay with the channel or follow the probe ?
Martyn
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Moonwalker
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Re: 5244B - Channel A and Channel B not equal

Post by Moonwalker » Mon Oct 19, 2015 10:19 pm

Ohh... sometimes the mind forgets the simple things :)

It looks like it was the probe picking up more signal inductively. After carefully placing the probes close together I get same signal on both channels.

So is it normal for a probe to pick up some signal inductively when connected in circuit?

AndrewA
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Re: 5244B - Channel A and Channel B not equal

Post by AndrewA » Fri Oct 23, 2015 2:38 pm

Yes the scope probes can pickup RF if the signal is a high signal level.
The probe must have been picking up the RF from the buck converter itself.
Regards Andrew
Technical Specialist

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