I’ve recently bought a number of Epcos/TDK DC-link caps. They are a fairly recent developement and look quite different from other DC-links i've seen in that they are cylindrical and much larger than your usual DC-link. They are also somewhat cheaper. The colour is blue. One of the electrodes has four pins around the circumference and the other electrode is in the middle. The datasheet gives no clue on how they should be connected. I’ll be using them in tube amp power supplies and I wonder if anybody has any idea what is best. Should one or four of the outside electrodes be connected to positive, or should the middle electrode be connected to +?
These days I only use DC-links in power supplies and I retrofit DC-links in existing amps. All DC-links are bypassed with GTO caps. This is an explosive combination. You try it or you don’t know what you’re missing.
These days I only use DC-links in power supplies and I retrofit DC-links in existing amps. All DC-links are bypassed with GTO caps. This is an explosive combination. You try it or you don’t know what you’re missing.
If you have access to a benchtop digital voltmeter with 4-point Kelvin probes: congratulations, you'll be able to figure this out with high confidence.
Make your own large drawing (at least 10cm X 10cm) of the pin arrangement of the capacitor, and label the pins on the drawing A , B , C , D , E . It doesn't matter how you assign labels, but it does matter that you remember them. That's why you make a large drawing with easy to read text.
Now make 4-point resistance measurements between each pair of pins: A-to-B , A-to-C , A-to-D , A-to-E , B-to-C , B-to-D , B-to-E , C-to-D , C-to-E , D-to-E . That's ten measurements and you can use your college probability textbook to verify that there are indeed ten combinations of 5 things taken 2 at a time. It will be in the section named "Binomial Coefficient".
It's likely that some pin-to-pin resistances will measure less than 100 milliohms (0.1 ohms). We will call those "shorted together". Make a photocopy of your pin drawing and using a different color ink, draw on the photocopy and show the short circuits between the pins with sub-0.1 ohm resistance.
How many independent circuit nodes do you see on your drawing? If the answer is "two" then you've got a plain old ordinary 2-terminal capacitor, which happens to have more than one external pin on a terminal. If the answer is "more than two" then you'll need to perform more elaborate tests than simple pin-to-pin resistances.
Make your own large drawing (at least 10cm X 10cm) of the pin arrangement of the capacitor, and label the pins on the drawing A , B , C , D , E . It doesn't matter how you assign labels, but it does matter that you remember them. That's why you make a large drawing with easy to read text.
Now make 4-point resistance measurements between each pair of pins: A-to-B , A-to-C , A-to-D , A-to-E , B-to-C , B-to-D , B-to-E , C-to-D , C-to-E , D-to-E . That's ten measurements and you can use your college probability textbook to verify that there are indeed ten combinations of 5 things taken 2 at a time. It will be in the section named "Binomial Coefficient".
It's likely that some pin-to-pin resistances will measure less than 100 milliohms (0.1 ohms). We will call those "shorted together". Make a photocopy of your pin drawing and using a different color ink, draw on the photocopy and show the short circuits between the pins with sub-0.1 ohm resistance.
How many independent circuit nodes do you see on your drawing? If the answer is "two" then you've got a plain old ordinary 2-terminal capacitor, which happens to have more than one external pin on a terminal. If the answer is "more than two" then you'll need to perform more elaborate tests than simple pin-to-pin resistances.
I’d probably agree, but I just wanted to hear if there are any different views worth considering.
Oh yes, and all of the Google search hits overwhelmingly agreed with each other; most of them gave the very same answer to the question. You will need to exert yourself to discover whether those search hits overwhelmingly said "yea" or "nay".
From where are you sourcing your GTO capacitors? A quick search only realized a small selection available here in the U.S. from supplier Mouser. The smallest value being a Wima 3.0uF @ $43 each.