Thanks for the informative video Jamie! You especially revealed to me how easy it is to use the peak-hold function of a spectrum analyzer, and a manually swept frequency source, to do essentially the same job as a network analyzer; nice!
Jamie. Nicely demonstrated. I appreciate the practical demonstration avoiding tedious physics to make a point. Your early explanation of magnetic field was appropriate. I wouldn't let anyone discourage your method of presentation; obviously you are well qualified in physics.
Jamie, instead of using a separate signal generator, you could use the spectrum analyzer's built-in tracking generator output as your signal source. Since it tracks the spectrum analyzer's scanning exactly, you would get a smoother curve without any manual knob turning.
Thanks Jamie, you have done the exact same experiment I had in mind for visualizing what those ferrite's get up to. I could spend all day with that equipment you have there. I'm still trying to figure out what Signal Gen and Scope I need for my lab.
Thank you. I enjoyed your video. Your covered a lot in such a short video. I wish my physics instructors and engineering mentors had been half as good as you. Thanks, again.
This looks like a differential mode application instead of a common mode application like how they are usually used. Could you design an experiment to demonstrate the effect in the common mode application?
I sometimes get MASSIVE Interference from my PC Tower & Marshall Guitar Amp while playing along to songs on RU-vid. The computer glitches with a loud BUZZ & a frozen blue screen. I can't move the PC away from the Amp (they are 2-3ft apart & you're saying one on these coils on the PC & Amp power cable going in to wall will do the trick, or do I have to do more than one per power wire? Thanks
So according to this adding the ferrite bead to my amplifiers power cable wouldnt compromise the powersource but will filter high frequency noise right?
Jose Martin for this demonstration the choke must be on only one wire, otherwise no difference would be seen on the SA. About putting more turns - there might be an issue with saturation, so one can not say it would work just as well without knowing the material etc.
Simon's right. Typically Chokes are used for common mode noise, and common mode noise is much smaller in amplitude than the differential signal. So when both wires are placed inside the choke at the same time, the two wires differential signals produce opposite magnetic noise and can't cause saturation in the choke. And common mode noise is so much smaller I've never heard of saturation being an issue there. But if only one wire is placed inside, saturation can be a problem.
Very interesting presentation. I studied EE for a while 40 years ago and remember some of it. I have a plasma tv that is causing massive RFI on my HF radio. Would a choke help and where would I put it? TV, antenna lead to the radio or elsewhere?
Hello Jamie, Would a ferrite chokes work to remove rfi in ham radio gear from powerline transformers etc.? Any help would be greatly appreciated. So I can make a decision if I should purchase it them.
From what I documented myself I learned that materials 75 and 31 work good for low and high frequencies, material 43, 44 and economical 46 for broadband frequencies, and material 61 for high frequencies.
would you be kind enough to help me ? i want to add a ferrite bead to usb 5v on a diy charger im building but im unsure what value bead to use. i read some use 600R and others say 33R. the bead will be rated for 4A..
I get that this is a student exercise, but it's kind of off target. First, just in terms of validating the test setup, why on earth does the 0-20MHz signal generator have such a wildly fluctuating (voltage) amplitude as recorded by the spectrum analyzer? That already suggests something fishy. Next, given that the point of the demo is to examine a magnetic phenomenon, we're vitally interested in the current, and consequently in the load impedance. Is the spectrum analyzer set to high Z input, or 50 ohms, or what?
Poor video unfortunately. You failed to mention the difference between common mode chokes, differential mode chokes and ferrite beads. Also no mention of the fact that beads are designed to have a very lossy ferrite material. No mention that insertion loss is related to the ratio of bead impedance to load impedance.
She says the flux in the ferrite bead is proportional but not directly proportional to the magnetic field a it is in a linear medium i think this covers your lossy material point (to some extent at least !). I think she was simply trying to show the usefulness of ferrite beads .
@Roger Onslow perhaps you need to create some content of your own and show us exactly what you want and allow us to critique your video. She did exactly what she said the video was about. All of your topics are off topic and therefore moot.
