Disc Capacitor E-Series Values: 114 of 929 Walsin Rows Are Finer Than Their Tolerance Implies, and 17 Fit No E24 Step

Walsin’s disc capacitor values do not follow one preferred series per tolerance. We placed all 929 rows on E6, E12 and E24: 527 sit on E6, 251 on E12, 134 on E24 and 17 on none, and 114 (12.3 percent) are finer than the series their tolerance conventionally pairs with. We have not seen this counted anywhere.

Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the ceramic disc capacitor parametric export published by Walsin Technology (Walsin): 929 rows, and no datasheet for any of them. This post is written from that one file. Every part number below is real. A design that quotes a value from a preferred series expects the catalogue to hold it, and a buyer who sets a tolerance expects the ladder to be the one that tolerance usually implies. We checked both expectations against the data.

Which E-series do Walsin’s disc capacitor capacitance values fall on?

Mostly E6, then E12, then E24, with a small remainder that fits none. We parsed all 929 rows, converted every capacitance to picofarads, and reduced each to its significand (47 pF, 470 pF and 4700 pF are all 4.7). We then asked whether that number belongs to E6, E12 or E24. 527 rows (56.7 percent) sit on E6, 251 (27.0 percent) on E12, 134 (14.4 percent) on E24, and 17 (1.8 percent) on none of the three.

The 929 rows hold 58 distinct capacitance values: 20 on E6, 18 on E12 only, 17 on E24 only, and 3 on none. A Y5V buyer sees a short ladder, 75 of 79 rows on E6. An SL buyer sees E24 in full, plus 8 exceptions.

Which tolerances carry values finer than their usual E-series?

Every tolerance except plus or minus 5 percent carries some. We took the pairing the three series are conventionally built for (E6 with plus or minus 20 percent, E12 with plus or minus 10 percent, E24 with plus or minus 5 percent) and counted the rows whose value is finer than that. 114 of 929 rows break the pairing: 73 at plus or minus 20 percent, 24 at plus or minus 10 percent, 9 at plus 80 minus 20 percent and 8 at plus or minus 5 percent.

The plus or minus 20 percent line is the surprise. More than one in four rows at that tolerance carries a value beyond E6, such as 3.9, 2.7 or 5.6. The wide tolerance means the 3900 pF part and the 4700 pF part overlap, and the catalogue lists both. Our earlier post on disc capacitor tolerance showed 22 pairs of parts that differ only in the tolerance letter; this is the capacitance-ladder side of the same question.

Which three values fit no E24 step at all?

50 pF, 500 pF and 5000 pF, and all three have a significand of 5.0. We listed every row that fits no series. The 17 rows are 8 parts at 50 or 500 pF with plus or minus 5 percent, 3 at 5000 pF with plus or minus 10 percent, 5 at 5000 pF with plus or minus 20 percent and 1 at 5000 pF with plus 80 minus 20 percent.

Round numbers are the likeliest reason, because 50, 500 and 5000 are the values a designer picks when the circuit has no preferred-value constraint. But the file does not say, and we hold no datasheet to ask. What it does say is that a selector rounding to the nearest E24 value would silently convert 50 pF to 47 or 51 pF on 6 of the 17 rows, all of them safety-series parts. Six of the 17 rows are 50 pF safety-series parts, where the rating matters. Do not round those.

Does Walsin write the same disc capacitance in two units?

Yes, for 10,000 pF. The Capacitance column holds 59 distinct strings for 58 distinct values, and the extra string is one value written two ways. 10,000 pF appears as 0.01uF on 28 Class II rows and as 10000pF on 4 safety AC-series rows. The part number code on all 32 is 103.

A filter on the string 10000pF returns 4 of the 32 rows that hold 10,000 pF, 12.5 percent. The unit follows the series: every Class II HI-K row from 10,000 pF up is written in microfarads, as 0.01uF, 0.02uF or 0.022uF, 33 rows in all. For the separate and larger problem with the code 103 on one safety part, see the capacitance code post.

What should a selector do with disc capacitance values?

Normalise to picofarads before comparing, and never round to a preferred series. The export gives you 929 values, and three things about them are measured above. Three rules follow.

1. Convert every value to pF and keep the original string beside it. Otherwise 10,000 pF returns 4 of 32 rows.
2. Do not snap a value to E6, E12 or E24. 17 rows fit no E24 step, and 6 are safety-rated parts.
3. Do not infer a tolerance from the value, or a value from the tolerance. 114 rows break the usual pairing, and 73 of them are at plus or minus 20 percent.

None of the 929 disc capacitor part numbers appears in our ready-stock snapshot of 1,125 part numbers as at 23 September 2026, so the ready stock page will not list one today. Ask us about the part you need. The family page is disc capacitors, and our free cross-reference tool states differences from your original rather than hiding them behind a tick.

The short version

Walsin’s 929 disc capacitor rows hold 58 distinct values: 527 rows on E6, 251 on E12, 134 on E24, 17 on none. 114 rows (12.3 percent) carry a value finer than their tolerance’s conventional series, 73 of them at plus or minus 20 percent. The 17 off-series rows share one significand, 5.0, at 50, 500 and 5000 pF. 10,000 pF is written 0.01uF on 28 rows and 10000pF on 4. We hold no disc datasheet, so we will not tell you what Walsin intends. We will show you the string the file holds. Qualification stays with you; confirm against both datasheets and qualify in your own circuit.

Send us the capacitance and tolerance on your drawing, and we will tell you which Walsin disc rows share the value and which differ in tolerance, rating or body. And a question back: if your library rounds 50 pF to 47, which of your designs notices?

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