Disc Capacitor Capacitance Code: 1 of 929 Walsin Rows Disagrees, and Code 103 Means Three Different Things

We decoded the disc capacitor capacitance code in all 929 part numbers in Walsin_DiscCap_ALL.xlsx and compared each one with the Capacitance column. 928 agree. One does not: YU0AS103M190, whose code says 10,000 pF and whose column says 1000 pF. And code 103 is the only one of 58 codes that maps to three different column strings.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds Walsin Technology (Walsin) ceramic disc capacitor parametric export of 929 rows and no disc capacitor datasheet of any kind — none of our 28 Walsin datasheets covers this line. This post is written from that single export file. Every part number below is real. For a United States buyer putting a Y capacitor across an isolation barrier, one wrong capacitance is a leakage-current failure at the test bench, not a cosmetic data problem.

Can I read the capacitance off a Walsin disc capacitor part number?

On 928 of 929 rows, yes. We parsed characters six to eight of every part number in the file and decoded them as two significant figures plus a decimal multiplier — 101 as 100 pF, 472 as 4700 pF, 103 as 10,000 pF. Then we normalised the Capacitance column to picofarads and compared. 928 of the 929 rows agree exactly. One disagrees. Our own earlier audit of the 367 safety certificated rows found the same single exception; extended to all 929 rows, including the 562 non-safety parts, the population figure is unchanged at 1 of 929.

Part number	Code	Code decodes to	Capacitance column	Series	Match / mismatch
YP500103K100	103	10,000 pF	0.01uF	Class II HI-K	Match on value, mismatch on unit — microfarads, not picofarads
YV0AC103M140	103	10,000 pF	10000pF	X1/Y2 AC series	Match — code, value and unit all agree
YV5AC103M140	103	10,000 pF	10000pF	X1/Y2 AC series, 500 V	Match — code, value and unit all agree
YU0AS472M140	472	4700 pF	4700pF	X1/Y1 AS series	Match — code, value and unit all agree
YU0AS102M080	102	1000 pF	1000pF	X1/Y1 AS series	Match — code, value and unit all agree
YU0AS103M190	103	10,000 pF	1000pF	X1/Y1 AS series	Mismatch — a factor of ten, the only one in 929 rows

That is a 99.89% hit rate on the code, which is far better than the file’s other columns manage. It is also why the single exception matters: a decoder that is right 928 times teaches an engineer to trust it.

Which disc capacitor part number disagrees with its own capacitance column?

YU0AS103M190. It is a Y5U dielectric X1/Y1 safety certificated disc in the AS series, rated X1 760 Vac and Y1 500 Vac, ±20%. Its code reads 10,000 pF. Its Capacitance column reads 1000 pF. We have published this one before and we re-measured it for this post against the full 929 rows rather than the 367 safety rows alone.

The reason it is not a harmless typo is that 1000 pF is already taken in the same series. YU0AS102M080 is the same dielectric, the same tolerance, the same X1 760 Vac / Y1 500 Vac rating, and its Capacitance column also reads 1000 pF. Read the column literally and Walsin publishes two distinct part numbers at the identical capacitance, dielectric, tolerance and rating inside a fifteen-part series, differing only in body size.

Part number	Code	Dielectric	Capacitance column	Tolerance	Rating	Match / mismatch vs YU0AS102M080
YU0AS102M080	102	YU(Y5U)	1000pF	±20%	X1-760Vac / Y1-500Vac	Match on all five fields — this is the reference row
YU0AS103M190	103	YU(Y5U)	1000pF	±20%	X1-760Vac / Y1-500Vac	Mismatch — code says 10,000 pF, and the body code is five steps larger
YU0AS222M120	222	YU(Y5U)	2200pF	±20%	X1-760Vac / Y1-500Vac	Mismatch — 2.2x the capacitance, two body steps larger
YP0AS102K110	102	YP(Y5P)	1000pF	±10%	X1-760Vac / Y1-500Vac	Mismatch — different dielectric and tolerance at the same value

Does the lead spacing code in the part number settle which figure is right?

It points hard at 10,000 pF. The last three digits of every Walsin disc part number carry a body or lead-pitch code, and we tabulated all 929 of them. Twelve values are in use: 040, 050, 060, 070, 080, 090, 100, 110, 120, 130, 140 and 190. 190 appears on exactly one row in 929 — YU0AS103M190. The next largest value in the whole file is 140, on 7 rows. There is no 150, no 160, no 170 and no 180 anywhere in the export.

Inside the AS series the code rises monotonically with capacitance, and we checked all fifteen rows. On the Y5U ladder it runs 080 at 1000 pF, 090 at 1500 pF, 120 at 2200 pF, 120 at 3300 pF, 130 at 3900 pF and 140 at 4700 pF. 190 continues that progression. Reading the Capacitance column literally would put a 1000 pF part at the largest body size in the entire 929-row file, five steps above the 1000 pF part that already exists in the same series.

Part number	Code	Capacitance column	Body code	Match / mismatch vs the AS series body ladder
YU0AS102M080	102	1000pF	080	Match — smallest body on the Y5U ladder, lowest capacitance
YU0AS222M120	222	2200pF	120	Match — body grows with capacitance
YU0AS472M140	472	4700pF	140	Match — largest body at the top of the published ladder
YU0AS103M190	103	1000pF	190	Mismatch — the only 190 in 929 rows, carrying the file’s lowest-but-one capacitance

We have not seen this counted anywhere. The body code corroborates the part-number capacitance code and contradicts the Capacitance column, on the one row in 929 where the two disagree.

Does any capacitance code in the file mean more than one thing?

One code does, and only one. We grouped all 929 rows by capacitance code and counted the distinct Capacitance column strings under each. 57 of the 58 codes in the file map to exactly one string. Code 103 maps to three: 0.01uF on 28 rows, 10000pF on 4 rows and 1000pF on 1 row.

Capacitance code	Column strings under it	Rows	Match / mismatch across the code
102	1000pF only	59	Match — one code, one string, one value
472	4700pF only	46	Match — one code, one string, one value
223	0.022uF only	4	Match — one code, one string, one unit
103	0.01uF, 10000pF, 1000pF	33	Mismatch — three strings, two units, and one value a decade out

The same census reads the other way too. 1000 pF is the only capacitance value in the file reachable from two different codes — 102 on 59 rows and 103 on one. Every other value in the range has exactly one code. So a sourcing engineer filtering the export for 1000 pF collects 60 rows, of which 59 carry the code that means 1000 pF and one carries the code that means 10,000 pF.

The unit split behind this is ours and already published: 896 of the 929 rows state capacitance in picofarads and 33 in microfarads, and the split follows the series rather than the value. The rating column has its own version of the same problem, counted in the disc capacitor UR column holds two incompatible rating systems. The dielectric codes are decoded in disc capacitor temperature coefficient codes.

Does the tolerance letter agree with the tolerance column on all 929 rows?

Yes, on all 929, with zero exceptions. This is the cleanest field in the file and we checked every row. Character nine of the part number carries the tolerance letter, and we cross-tabulated it against the Tolerance column: J appears on 304 rows and the column reads ±5% on all 304. K appears on 309 rows and reads ±10% on all 309. M appears on 270 rows and reads ±20% on all 270. Z appears on 46 rows and reads +80%/−20% on all 46.

Tolerance letter	Rows	Tolerance column	Exceptions	Match / mismatch
J	304	±5%	0	Match on all 304 rows
K	309	±10%	0	Match on all 309 rows
M	270	±20%	0	Match on all 270 rows
Z	46	+80%/−20%	0	Match on all 46 rows

304 plus 309 plus 270 plus 46 is 929. No fifth letter appears and no row is blank. That is worth stating plainly, because it tells you where a decoder is safe and where it is not: on this line, trust the tolerance letter without checking, and check the capacitance code against the column every time.

What should a United States buyer do with a Y capacitor whose capacitance is in dispute?

Read the column and the code, and when they differ, stop. A Y capacitor’s capacitance sets the leakage current across the isolation barrier, and that is a measured compliance figure on a United States production line, not a tolerance band. One decade of error is not a rounding question.

1. Decode the code and compare it with the column on every disc line. On 928 of 929 rows they agree. On YU0AS103M190 they are a factor of ten apart, and the body code sides with the part number.
2. Cross the whole input stage in one pass. Paste up to 500 part numbers or drop your Excel or CSV into the free cross reference tool, filter for safety certified parts, and read every stated difference. We will not tell you a part is equivalent. We will show you where it differs.
3. Check what was physically in Hong Kong on ready stock — a dated snapshot as at 23 September 2026, not a live feed. All 929 disc capacitor part numbers had zero representation in that snapshot, so a Y capacitor is an order, not a pull.

The full line sits on the Walsin ceramic disc capacitor page.

The short version

The disc capacitor capacitance code is the most reliable field in Walsin’s 929-row disc export: 928 of 929 rows agree with the Capacitance column. The single exception is YU0AS103M190, whose code means 10,000 pF against a column reading 1000 pF, in a series where YU0AS102M080 already occupies 1000 pF on the same dielectric, tolerance and rating. Its body code 190 appears on one row in 929, five steps above the 1000 pF part, which sides with the code rather than the column. Code 103 is the only one of 58 codes mapping to three column strings, and 1000 pF is the only value reachable from two codes. The tolerance letter, by contrast, agrees on all 929 rows with no exceptions. We hold no disc capacitor datasheet. Qualification stays with you.

Send us the isolation-barrier lines off your United States bill of materials and we will return Walsin candidates field by field, with the capacitance decoded from the part number and from the column, and the two shown separately where they differ. If your library already carries a 1000 pF entry for YU0AS103M190, where did that number come from — the code, or the column?

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Frequently asked questions

<!– wp:rank-math/faq-block {"questions":[{"id":"faq-question-01","title":"How do I read the capacitance code in a Walsin disc capacitor part number?","content":"Characters six to eight carry two significant figures plus a decimal multiplier, so 101 is 100 pF, 472 is 4700 pF and 103 is 10,000 pF. We decoded all 929 rows in Walsin’s disc capacitor export and compared each with the Capacitance column: 928 agree exactly.”,”visible”:true},{“id”:”faq-question-02″,”title”:”Which Walsin disc capacitor part number has the wrong capacitance in the export?”,”content”:”YU0AS103M190. Its code decodes to 10,000 pF and its Capacitance column reads 1000 pF. It is the only disagreement in all 929 rows. We first found it across the 367 safety certificated rows and have now extended the audit to the full 929, which leaves the figure unchanged at one.”,”visible”:true},{“id”:”faq-question-03″,”title”:”Does the body code in the part number confirm the capacitance?”,”content”:”On this part it does. The last three digits carry a body or lead-pitch code, and 190 appears on exactly one row in 929. The next largest value in the file is 140, on 7 rows. Inside the AS series the code rises with capacitance, so 190 fits 10,000 pF and not 1000 pF.”,”visible”:true},{“id”:”faq-question-04″,”title”:”Does any capacitance code in Walsin’s disc export mean more than one thing?”,”content”:”Code 103, and only code 103. We grouped all 929 rows by code: 57 of 58 map to one Capacitance string each. Code 103 maps to three — 0.01uF on 28 rows, 10000pF on 4 and 1000pF on 1. Read the other way, 1000 pF is the only value reachable from two codes.”,”visible”:true},{“id”:”faq-question-05″,”title”:”Is the tolerance letter in a Walsin disc part number reliable?”,”content”:”Yes. We cross-tabulated character nine against the Tolerance column on all 929 rows with zero exceptions: J is ±5% on 304 rows, K is ±10% on 309, M is ±20% on 270 and Z is +80%/−20% on 46. That totals 929. No fifth letter appears and no row is blank.”,”visible”:true},{“id”:”faq-question-06″,”title”:”Do you hold a Walsin disc capacitor datasheet?”,”content”:”No. We hold 28 Walsin datasheets, 451 pages, and not one of them covers the disc line. All 929 disc part numbers have no datasheet in our library, and zero of the 929 rows carries a certificate number in the export. For specifications go to Walsin’s own site, and ask Walsin for the approval sheet for your exact part number.”,”visible”:true}],”listStyle”:””,”titleWrapper”:”h3″,”titleCssClasses”:””,”contentCssClasses”:””,”sizeSlug”:””} –>

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