300 pf, 10 KV Peak, Jennings Type UCS-300-10S


Capacitance 10-300 pf
Voltage Rating 10 KV
Current Rating 50 Amps RMS

The capacitor is a Glass, VARIABLE capacitance, vacuum capacitor. 10-300 pf capacitance rated at 10 KV peak voltage. These units are removed from equipment, checked, and guaranteed.

2 in stock

Jennings Type UCS-300-10S glass, vacuum, variable capacitor

Rated Capacitance 10-300 pF
Peak Voltage 10 KV
Current Amps (RMS) Maximum 50 Amps
Shaft Diameter 1/2 inch
Turns for Full Travel Max 22
Important Dimensions
Max Length 8.75 in / 222.25 mm (including shaft)
Max Diameter 3.25 in / 82.55 mm
Weight 28.29 oz / 802.01 g
Permanently mounted flange with 4 drilled holes for front end mounting and FM0B Flange needed for rear end mounting, shown in photo, but not included. (Available at additional cost) See our flange page: Vacuum Capacitor Flanges
Condition Removed from equipment, checked, guaranteed
(Other variations of this capacitor are sometimes available, inquire)
UCS-200-7.5S UCS-200-10S UCS-200-15S
UCS-300-7.5S UCS-300-10S UCS-300-15S
UCS-400-7.5S UCS-400-10S UCS-400-15S
UCS-500-7.5S UCS-500-10S UCS-500-15S


“Out of spec” and “budget” capacitors:  

If you want the quality and performance of vacuum capacitors, but the budget just won’t allow it, (or if you are just looking to save some money) we frequently have “out of spec” capacitors. These capacitors do not meet the specifications for the particular model. This can happen because of many reasons, but they are still perfectly usable in other capacitance ranges or maximum voltages.

For instance, we might have a type that is listed at 15 kv, but tests good to 12 kv.  In this case, we will not sell it to a user who needs 15 kv ratings, but if you need only 5 kv, 7.5 kv, or 10 kv, this capacitor would do nicely.  If you want us to check our “out of spec” shelves for current stock, just tell us your capacitance range and voltage requirements (and current rating if you know it… or approximate power level) and we will let you know what we have available at steep discounts! Inquire here!


We also frequently have in stock many vacuum capacitors which have cosmetic blemishes such as dents, which would not meet our high standards for regular sale, but which still check good, both in range, and in their ability to withstand voltage.

Some dents will damage or totally destroy a capacitor. Others, if they occur in just the right places, cause no harm at all. We have the knowledge and test capability to make these determinations, and if they pass our stringent testing, sell these units at discounted prices with our regular guarantee! If interested in these units, please inquire as to current availability.

If you don’t see what you wanted: 

These pages show only a fraction of the stock we have available. We have many thousands of vacuum capacitors, both fixed and variable, as well as vacuum relays. This stock changes daily. If you have requirements for items not listed in these product lines, please Email, and our knowledgeable staff will search our inventory. (Don’t forget to give us your email address and contact information!)

Did you know?

We will buy your used and overstock vacuum capacitors and vacuum relays?

Max-Gain Systems, Inc. is the one source to liquidate your excess inventory of vacuum capacitors and vacuum relays. REDUCE warehousing costs, REDUCE aging inventory & OPTIMIZE warehouse space by selling us your unwanted inventory. New and old stock, used and even removed from working equipment, one unit to one thousand plus, you can make money as well as go green. In addition, most of the surplus items we buy are able to go right back into facilities and into the hands of individuals that need a low cost replacement to keep their plants and broadcast stations up and running.

Sell your New and Used Overstock vacuum capacitors and vacuum relays by emailing us. Please include how many, the manufacturer’s part number, and their condition, along with your full contact information. We will reply within one business day.


Additional information

Shipping Weight 29.00 oz
Shipping Dimensions 10.00 × 10.00 × 15.00 in


Min Capacitance

Max Capacitance


10 KV

Current Rating

50 Amps

Shaft Diameter

1/2" OD Shaft


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