madswitcher

Unusual Capacitor
« on: August 02, 2018, 05:36:56 PM »
Hi Folks,

I have come across an unusual type of capacitor that I would appreciate some help in identifying - see the attached photos.

It has three pins, two long and one short.  The two longer ones have a measured capacitance of 0.996uF between them (as written on the can top) and both long pins to the short pin measures 0.5pF.  The short pin is not connected to the can.  It is obviously Russian, nominal 1uF 2%.  I suspect made in week 8, 1987.

Any thoughts

Regards

Mike


madswitcher

Re: Unusual Capacitor
« Reply #1 on: August 02, 2018, 05:38:04 PM »
another photo

madswitcher

Re: Unusual Capacitor
« Reply #2 on: August 02, 2018, 05:38:41 PM »
and a third

scott2000

Re: Unusual Capacitor
« Reply #3 on: August 02, 2018, 05:39:35 PM »
The short pin must just be for support???

"Give me a 25-stack of 9V batts, I'll monitor my truck's spark or fuel injection on the magic eye." PRR

madswitcher

Re: Unusual Capacitor
« Reply #4 on: August 02, 2018, 05:46:01 PM »
The short pin must just be for support???

Hi Scott, I'll take that as serious face value.   :)   I don't think so as there are three small nipples on the case bottom to space it about 0.5mm above a circuit board when  installed.

radardoug

Re: Unusual Capacitor
« Reply #5 on: August 02, 2018, 06:31:07 PM »
He's right, it is for support.

madswitcher

Re: Unusual Capacitor
« Reply #6 on: August 03, 2018, 04:12:57 AM »
Please forgive the initial disbelief, but I think you guys are right: after ploughing more search time on the Internet I cannot get any other explanation, so it must be for location purposes.

Thanks

Mike

CJ

Re: Unusual Capacitor
« Reply #7 on: August 03, 2018, 04:33:08 AM »
those are called dummy pins, but usually you find them on heavier caps like this Cornell Dublier 10,000 uf @ 80 V>

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JohnRoberts

Re: Unusual Capacitor
« Reply #8 on: August 03, 2018, 10:33:11 AM »
yup  structural...

back in the day I would put products on the shaker table to find the weak sisters. The big green polyester caps that I liked for decent audio performance while still inexpensive, were not very strong, and could be found rolling around in the bottom of the case after an all night shake. 

JR
John Roberts
http://circularscience.com
Tune it, or don't play it...

ungifted

Re: Unusual Capacitor
« Reply #9 on: August 03, 2018, 11:00:11 AM »
Yes, it's K71-5 polystyrene capacitors, btw many people say good caps for audio.
Third pin is dummy pin for reliable PCB mounting.
http://diy-tubes.com - parts for guitar/studio gear


JohnRoberts

Re: Unusual Capacitor
« Reply #10 on: August 03, 2018, 11:34:35 AM »
Yes, it's K71-5 polystyrene capacitors, btw many people say good caps for audio.
Third pin is dummy pin for reliable PCB mounting.
I loved polystyrene dielectric for audio filters, but the capacitors were not very factory friendly.  The polystyrene  caps also generally used skinny wire leads, probably to conduct less soldering heat to the easily melted plastic capacitor body.

 JR
John Roberts
http://circularscience.com
Tune it, or don't play it...


 

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