Adjustable range of EPCOS tunable ferrite P-cores?
So, I've got a bunch of Epcos M33 P cores coming in today hopefully. The tolerance on the AL for the core is +/- 3%, much better than the 20-30% you get for non-gapped cores presumably because the air gap dominates and is quite precisely machined.
The cores that were immediately available just happen to have a threaded sleeve for an adjustment screw. We refrained form ordering some as the MOQ was high and we weren't sure how much adjustment you could get from them. Epcos haven't responded to my query on this yet and based on previous experience I might not hear anything back.
does anyone know what kind of adjustment you could expect from these? We only need enough to tune out the tolerance of the core. Basically we have to spend ￡800 to buy some and find out if we can do this and I'm looking for some confidence before deciding to try. I would have thought you'd get at least 3% no?
Thanks
James
The adjustment range is specified in individual P core datasheets, at least in my databook. It's at least +10%, up to +20% for some types. For some core sizes, adjusting srews with different color code are available. If the information is missing in the recent Epcos datasheets (I didn't check this) tell your intended core size.
I really can't find this information on the website. I've tried the material datasheet, the P core datasheet and anything I can see that might be related. 10%-20% is very good, are you sure this is for a gapped core like mine? It's just that the gap reduced the 20-30% tolerance to 3% so to get 10-20% out of an adjustment screw insert seems almost too good to be true! I would be happy with 3% adjustment though, just to remove the tolerance of the cores from my filter design.
Here's the respective chapter.
Thats brilliant, thanks very much. Has exactly what I needed. I couldn't find that document anywhere on their website!
Yes, Epcos has apparently stripped off a lot of valuable information from the old Siemens datasheets. The same problem turned out recently with typical Q curves that once have been there. I wonder which muggle has edited the literature?
If you need to get some prototypes, I remember that German distributor buerklin.com has stocked many of Epcos ferrite parts, including adjusting screws. It may be worth to browse the online catalog for the parts you want.
I wish I knew about these guys before! They seem to have everything...