Variable Vacuum Capacitors

Variable capacitors can be intentionally and repeatedly changed, both mechanically and electronically. Jennings variable vacuum capacitors are available with capacitance of 30 to 4,000 pF, withstanding voltage at 50/60 Hz in the range of 1.8 to 36 kV. The maximum operating current for variable vacuum capacitors is limited by temperature rise and working voltage.

Key Features

  • High voltage rating
  • High RF current ratings for normal convection cooling in ambient temperature of 25 °C (unless otherwise specified)
  • Maximum allowable temperature of 125 °C
  • Low losses
  • Self-healing
  • High altitude operation
  • Wide tuning ranges
  • Rotation in increase capacity: Counterclockwise
  • Any mounting position


  • Broadcast radio transmitters
  • Semiconductor manufacturing equipment
  • Plasma generating equipment
  • Industrial dielectric heating equipment
  • Power switching
  • Power interrupting
  • Avionic and mobile radio systems
  • Radar antenna switching
  • MRI and NMR
  • High voltage capacitor banks
  • Output filters
  • Coupling capacitors
  • Industrial RF

Product selection table

Serie Nr.Capacity max. (pF)Test voltage 60/50 Hz
CVDD-30307.5, 10, 15
CVDD-1001007.5, 10, 15
C/GCS-1001007.5, 10, 15
CVCD-2502503, 5
CVHP-25025045, 50, 55
CVHP-45045045, 50, 55
CSV1-5005003, 5
CVDD-5005007.5, 10, 15
M/CSVF-5005007.5, 10, 15
M/CSV5-5005005, 8
CVHP-65065045, 50, 55
CWV3-65065040, 45, 50
CVDD-7507507.5, 10, 15
CSV4-9009003, 5, 6
CSV1-100010003, 5
CVDD-100010007.5, 10, 15
CVHP-1000100040, 45, 50
CWV5-1000100040, 45, 50
M/CVCJ-100010003, 5
M/CSV5-100010003, 5
CVCD-150015003, 5
CVDP-150015007.5, 10, 15
CWV1-1600160055, 60
CWV2-1600160030, 35, 40
CWV3-1600160035, 40
CWV4-1600160050, 55, 60
CVCD-200020003, 5
CWV4-2050205040, 45, 50
CVDP-230023007.5, 10, 15
CVCD-300030003, 5

Capacitance tolerance

For the Jennings variable vacuum capacitors series, the low-end capacity will be equal to or less than the minimum rating. The capacitance change is substantially uniform with rotation and  there are no capacitance reversals. Capacitacne is within ±10% of the nominal value.

Torque/Direct pull

In variable capacitors, the linear sliding motion of the moving electrode assembly is converted to rotary tuning via a threaded shaft. The torque values given in the tables are the maximum torque needed to reach minimum capacitance when rotated with a standard lead screw; the torque required to tune away from minimum may be less than half this value. For most variable capacitors, direct pull tuning is an available option to rotary tuning.

Mechanical Life

The mechanical life of variable capacitors is related to length of stroke, speed of operation, bellows material and total number of cycles. Our most recent variable capacitor models are rated for >2 million cycles, ideal for the semiconductor processing industry.