KVI is a family of high-voltage non-insulated ceramic pulse capacitors — KVI-1, KVI-2 and KVI-3 — covering roughly 5 kV to 30 kV and 1.5 pF to 6,800 pF. Replacing them with the CV series mica capacitors is not just a change of supplier: it removes a temperature-drift problem.
Despite the high voltage, KVI capacitors are not vacuum capacitors and not mica capacitors: the dielectric is ceramic, and the case is non-insulated (the body is at the potential of one electrode), which is why they are mounted with an insulating bracket and clearance in the original design.
The three variants differ in voltage class: KVI-1 runs from roughly 5 kV to about 15 kV with a −60 °C to +125 °C rating, while KVI-2 and KVI-3 extend to about 30 kV with a −60 °C to +100 °C rating.
KVI-2 and KVI-3 use a low-frequency ceramic with a temperature coefficient group of N70. N70 is not a temperature-compensating group — its capacitance change over temperature can reach about −70 %. For circuits where capacitance value matters at all — resonant circuits, timing, voltage division — that drift dominates the behaviour of the equipment.
A mica dielectric holds capacitance far more tightly across the same temperature span. This is why a CV series substitution here should be evaluated as a performance change, and in most cases as an improvement, rather than as a like-for-like swap.
Two mechanical differences matter. First, the KVI case is live; a mica part with insulated construction changes the creepage and clearance picture, which normally improves but must be reviewed. Second, the KVI footprint is a specific outline — confirm the dimensional drawing before committing to the substitution.
| Parameter | KVI-1 | KVI-2 / KVI-3 | CV series |
|---|---|---|---|
| Dielectric | High-voltage ceramic | High-voltage ceramic, N70 | Mica |
| Voltage | ≈ 5 – 15 kV | ≈ 5 – 30 kV | 630 V – 20 kV (DC) |
| Capacitance | ≈ 1.5 – 6,800 pF | ≈ 1.5 – 6,800 pF | 100 pF – 2.2 µF |
| Temperature | ≈ −60 … +125 °C | ≈ −60 … +100 °C | −55 … +155 °C (+250 °C special) |
| Capacitance stability | Ceramic drift | Drift up to ≈ −70 % (N70) | Mica — far tighter over temperature |
| Case | Non-insulated | Non-insulated | Axial leaded |
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