Ceramic Disc Capacitor Selection: 328 of 534 Filled Cells Hold Only One Part

A ceramic disc capacitor selection across Walsin’s 929-row export is a grid of 58 capacitance values against 15 voltage ratings. We filled in all 870 possible cells. Only 534 are populated, and 328 of those — 61% — hold exactly one part number. Pick the wrong cell and there is no second candidate.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds Walsin Technology (Walsin)’s disc capacitor export, Walsin_DiscCap_ALL.xlsx, 929 rows and 11 columns. Every part number below is real, and every count is a count of part numbers, not pieces. We split the file along the line Walsin itself draws — 562 general-purpose rows rated in bare DC volts, and 367 safety-certificated rows rated in a compound AC string — because the two never share a rating and should not be read as one grid.

How big is the grid a ceramic disc capacitor selection actually has to search?

Fifty-eight capacitance values by fifteen voltage ratings, or 870 cells if every combination existed. We counted the distinct values in both the Capacitance and UR columns across all 929 rows: 58 capacitance values from 10 pF to 22,000 pF, and 15 voltage strings — seven bare DC steps and eight compound AC safety ratings. Multiplying them gives the full size of the decision space a selector is implicitly searching.

Grid dimension	Distinct values	Range
Capacitance	58	10 pF to 22,000 pF
Voltage rating (UR)	15	50 Vdc to 6,000 Vdc; X1-400 to X1-760 Vac
Theoretical cells	870	58 × 15

870 is the number a parametric search tool implies exists. Walsin_DiscCap_ALL.xlsx does not deliver it.

How many cells in that grid are actually filled?

534, which is 61.4% of the theoretical 870. We grouped all 929 rows by the exact (capacitance, voltage) pair and counted distinct non-empty cells. The remaining 336 cells — a capacitance and voltage combination with zero Walsin part numbers — are gaps a buyer only discovers by searching and getting nothing back.

	Theoretical cells	Filled cells	Cells with exactly 1 part	Share of filled cells that are single-part
Whole file (929 rows)	870	534	328	61.4%
General purpose, DC (562 rows)	399 (57 cap × 7 volt)	298	164	55.0%
Safety, AC (367 rows)	288 (36 cap × 8 volt)	236	164	69.5%

Both halves of the catalogue land in the same place: roughly six of every ten filled cells have no second candidate. We have not seen this grid-density figure counted anywhere.

Where does the shelf run thin as the DC voltage climbs?

Fast. We grouped the 562 general-purpose rows by their bare DC voltage step and counted how many distinct capacitance values each step still offers. At 50 Vdc, the lowest step, 54 of the 57 distinct capacitance values are available across 109 rows. At 6,000 Vdc, the highest step, only 16 capacitance values survive across 16 rows — and every one of those 16 rows is its own capacitance value, so the selection at 6,000 Vdc has zero redundancy anywhere on the step.

DC voltage step	Rows	Distinct capacitance values	Capacitance range
50 Vdc	109	54	15 – 22,000 pF
100 Vdc	103	52	15 – 22,000 pF
500 Vdc	87	48	18 – 10,000 pF
1,000 Vdc	106	46	15 – 10,000 pF
2,000 Vdc	100	45	15 – 10,000 pF
3,000 Vdc	41	37	10 – 4,700 pF
6,000 Vdc	16	16	10 – 100 pF

The part numbers at the top are SL602100J060 through SL602101J090, all Class I Temperature Compensation, all ±5%, one part per value, ten pF steps apart. If your design needs 56 pF at 6,000 Vdc, SL602560J080 is the only row in the file, and there is no second vendor code to check it against inside this catalogue.

Where does the safety shelf run thin as the AC rating climbs?

Similarly, and the top of the safety ladder is thinner than the bottom of the DC ladder. We ran the same count on the 367 AC safety rows. The busiest single cell in the entire safety grid — 1,000 pF at X1-440Vac/Y2-250Vac, X1-400Vac/Y1-250Vac, X1-440Vac/Y2-300Vac and two more ratings — holds 5 part numbers each. Move to the highest AC rating, X1-760Vac/Y1-500Vac, and the shelf drops to 15 rows total across the whole series, spanning capacitance from 10 pF to 24 pF only.

The practical read: the safety shelf is deepest in the common Y2 250/300 Vac band most mains filters specify, and it is a narrow, high-value band at the X1 760 Vac extreme that most designs never reach.

Which two capacitance values exist as exactly one part number in the whole file?

510 pF and 20,000 pF (written 0.02uF), and each is also pinned to a single voltage rating. We counted every distinct capacitance value against how many total rows carry it: 56 of the 58 values have 2 or more part numbers behind them, and exactly 2 values have exactly 1.

Part number	Series	Capacitance as published	Voltage rating	Match / mismatch vs “pick any 500-ish pF disc part at 50 Vdc”
SL500511J090	Class I Temperature Compensation	510 pF	50Vdc	Mismatch — the only row at 510 pF in the whole 929-row file; no second candidate at any voltage
ZV500203Z070	Class II HI-K	0.02uF (20,000 pF)	50Vdc	Mismatch — the only row at 20,000 pF; also the largest capacitance value with just one part behind it
YV500223M090	Class II HI-K	0.022uF (22,000 pF)	50Vdc	Match on family and voltage; mismatch — the catalogue’s single largest capacitance, but 3 part numbers back this one, not 1

A line item that asks for “approximately 500 pF, 50 V disc” can land on SL500511J090 by rounding and never notice it is the only row at that exact value in Walsin_DiscCap_ALL.xlsx — the next nearest capacitance values in the file are 470 pF and 560 pF, both with multiple candidates.

What does the busiest cell in the grid look like?

Seven part numbers, and it happens twice. We sorted all 534 filled cells by row count: the single busiest cell in the entire 929-row file is 1,000 pF at 2,000 Vdc, with 7 part numbers, and 2,200 pF at 2,000 Vdc ties it, also at 7. Both sit in the general-purpose DC half of the catalogue, not the safety half.

Capacitance	Voltage	Part numbers in the cell
1,000 pF	2,000 Vdc	7
2,200 pF	2,000 Vdc	7
4,700 pF	50 Vdc	6
10,000 pF	50 Vdc	6
10,000 pF	500 Vdc	6

Even the busiest cell in the file offers 7 candidates against a theoretical infinity of tolerance and dielectric combinations — not the deep shelf Walsin’s own 929-row export implies from its row count alone.

What should a buyer do with a shelf this uneven?

Check the cell before you commit to the value. A ceramic disc capacitor selection that starts from “I need roughly X pF at Y volts” can land on a cell with one part number and no fallback, or on a gap with zero. The trade press has reported passive component lead times stretching through 2026 as AI server and electric vehicle programmes draw on the same ceramic capacity, which makes a single-candidate cell a bigger risk than it would have been two years ago.

1. State the exact capacitance and voltage, then check the cell count before you design it in. A single-part cell is not wrong, but it deserves a second-source conversation before it reaches a BOM freeze.
2. Cross the whole BOM in one pass. Paste up to 500 part numbers or drop your Excel or CSV into the free cross-reference tool, and read the candidates and the gaps it returns rather than assuming depth that is not there.
3. Check what is physically in Hong Kong on ready stock before you commit to a slot — a dated snapshot as at 23 September 2026, not a live feed.

We hold no disc capacitor datasheet among our 28 Walsin datasheets, so every figure above is the export’s own text, taken straight from Walsin_DiscCap_ALL.xlsx — ask us for the series data on Walsin’s own site if you need a drawing. For the two rating systems sharing one column, see the disc capacitor UR column holds two incompatible rating systems. For the chip-side comparison, see Y capacitor safety selection: disc covers 400-760 Vac, chip S2 stops at 310. The range sits on the Walsin disc capacitor page.

The short version

A ceramic disc capacitor selection across Walsin’s 929-row export has 870 theoretically possible capacitance-and-voltage cells. We filled the grid ourselves: only 534 cells are populated, and 328 of those — 61% — hold exactly one part number. The shelf thins fast as voltage climbs — 54 capacitance values at 50 Vdc, 16 at 6,000 Vdc with zero redundancy at any of them. Two capacitance values, 510 pF and 20,000 pF, exist as a single part number each in the whole file. The busiest cell anywhere is 7 part numbers, at 1,000 pF and at 2,200 pF, both at 2,000 Vdc. Qualification stays with you.

Send us the exact capacitance and voltage off your BOM and we will tell you how many Walsin part numbers actually sit in that cell — not how many rows the file has, but how many candidates you really have at that one point.

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Frequently asked questions

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