I’ve been exploring some of the through-hole ceramic capacitor kits and am curious about the material used for the leads. Is there somewhere I can find that information? While I know that most capacitor leads are typically made of steel, I’m specifically looking for capacitors with nonferrous leads. Can anyone provide information on whether DigiKey offers such capacitors?
Some manufacturer’s use copper core leads but that is often an option with tin/lead plating, example is Kemet’s Goldmax series, DigiKey does not stock the copper core option in that case.
TDK has some copper core leads like the FK Series
But if you need truly non-magnetic it would take more digging, some ceramics use ferrous metals in on the capacitive plates internal to the ceramic.
Some manufacturers make full material declarations publicly accessible, but if this is for something critical that needs to be non-magnetic you’re best checking with the manufacturers, if they have components that are usable in medical imaging applications they often advertise that fact.
Out of curiosity, what is your application? I would like to know more about the specific problem you are working to solve as I am always looking to learn more about electronics.
With this information we may be able to better assist you select the desired components.
Hello, I’m trying to create a prototype for an MRI-safe medical device, which is why the capacitors need to be non-ferrous. Any assistance or guidance you can provide would be greatly appreciated. Thank you!
I don’t know that any of the through hole ceramics DigiKey carries are going to be non-magnetic enough for medical imaging applications, it’s not just the leads, I think they often use ferrous materials internal to the ceramic.
Fascinating application. I have questions. You likely already know the answers, but they may be of interest to our readers.
What is the nature of the MRI field? For example, suppose we made a coil consisting of 20 turns of insulated wire. To the ends of this wire, we attach an LED.
Would the LED light up when placed inside the MRI machine?
As I understand the MRI machine, there are three fields of interest including:
- a tremendous static field – no impact on the coil of wire. That is, once inside the field there is no delta to induce a voltage in our coil.
- gradient fields in X, Y, and Z – would likely induce a voltage in the coil.
- RF field – could induce a voltage into the coil especially if the coil was somehow tuned to the proper frequency
The video below shows the strength of the static field as it “holds” an aluminum panel against gravity.
As you can see by my questions, I don’t have a good answer for you. Perhaps you can consult to the engineers who are working to design MRI safe pacemakers. It’s possible that academic paper have been written about the subject.