Siemens MP capacitors in a strange design.

[rock soderstrom]

I got some old Siemens MP capacitors in a design that I am seeing for the first time.

One electrode of the capacitor is connected to the two solder terminals, the other is the case.

What is the idea behind this? What advantages does this offer?

The capacitors are obviously used, but they measure like new ones. The caps were built in 1961 and have a very high quality case, I think they were expensive.

 

[radardoug]

Thats a feedthru with cap attached.

 

[user 130681]

They are for decoupling and are as stated above, feedthrough types used in HF aplications.Your lower photo shows the schematic.
Some had built in inductors but not this one as can be seen by the schematic symbol.

 

[rock soderstrom]

They are for decoupling and are as stated above, feedthrough types used in HF aplications.Your lower photo shows the schematic.
Some had built in inductors but not this one as can be seen by the schematic symbol.

Thanks Doug & Jon!

That's interesting and also explains why I haven't encountered them yet, since I haven't had anything to do with HF.

Normally I am rather suspicious of old capacitors but these I will use again, probably in a microphone for local PSU decoupling. As I said, they measure like new and have stood the test of time much better than their unsealed relatives.