Disc capacitor tolerance is one letter in a Walsin part number, and 22 pairs differ in that letter alone. Of 929 disc rows, 18 pairs widen plus or minus 20 percent to plus 80 minus 20 percent. On a 10,000 pF part, the upper limit moves from 12,000 to 18,000 pF.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the disc capacitor parametric export from Walsin Technology (Walsin): 929 rows, four tolerance values. This post is written for buyers and engineers in Romania who cross a disc capacitor and need to know when a one-character change is a different part. It uses that export only, since we hold no disc capacitor datasheet. Every part number below is real.
How many Walsin disc capacitor part pairs differ only in the tolerance letter?
22 pairs, 44 of 929 rows. We parsed all 929 part numbers, removed the ninth character, which is the tolerance letter, and grouped what was left. 22 groups hold two rows. In every one the series, dielectric, capacitance, rated voltage and body code are identical and only the letter changes. 18 pairs are M against Z, 4 are J against K.
| Pair type | Pairs | Rows | Where | Real parts | Match / mismatch |
|---|---|---|---|---|---|
| M against Z: plus or minus 20 percent against plus 80 minus 20 percent | 18 | 36 | 16 in Y5V, 2 in Z5U | YV500102M040, YV500102Z040 |
Match on everything printed except the tolerance string |
| J against K: plus or minus 5 percent against plus or minus 10 percent | 4 | 8 | Class I SL only | SL501101J050, SL501101K050 |
Match on everything printed except the tolerance string |
| Every other row | 0 | 885 | no twin differs by a letter | YU500103M070 |
Mismatch against the idea that tolerance is a free choice: no sibling exists |
We have not seen this counted anywhere. The 929 rows hold 4 tolerance letters, J on 304, K on 309, M on 270 and Z on 46, and each letter maps to exactly one tolerance string, 929 of 929. 885 parts, 95.3 percent, have no sibling that differs in tolerance alone.
What does the tolerance letter change in the capacitance band?
The upper limit by 60 percentage points on a Z part, and both limits by 5 points on a K part. We applied each printed tolerance to the nominal value of a real pair. A 10,000 pF Y5V part spans 8,000 to 12,000 pF at M and 8,000 to 18,000 pF at Z. The lower limit matches, and the upper limit is 6,000 pF higher.
| Real pair | Nominal | Rated voltage | Band at the first letter | Band at the second letter | Match / mismatch |
|---|---|---|---|---|---|
YV500103M060, YV500103Z060 |
10,000 pF | 50 Vdc | 8,000 to 12,000 pF | 8,000 to 18,000 pF | Lower limit match; upper limit mismatch by 6,000 pF |
YV500102M040, YV500102Z040 |
1,000 pF | 50 Vdc | 800 to 1,200 pF | 800 to 1,800 pF | Lower limit match; upper limit mismatch by 600 pF |
ZU102103M100, ZU102103Z100 |
10,000 pF | 1,000 Vdc | 8,000 to 12,000 pF | 8,000 to 18,000 pF | Lower limit match; upper limit mismatch by 6,000 pF |
SL501101J050, SL501101K050 |
100 pF | 500 Vdc | 95 to 105 pF | 90 to 110 pF | Mismatch at both limits by 5 pF |
SL102470J050, SL102470K050 |
47 pF | 1,000 Vdc | 44.65 to 49.35 pF | 42.3 to 51.7 pF | Mismatch at both limits by 2.35 pF |
The arithmetic is on printed strings. A Z part is not a worse part. It is a part the maker specifies over a wider band, and a circuit that tolerates 18,000 pF may not tolerate it at the top of a hold-up or timing network. How the export writes 10,000 pF as 0.01 uF on some rows is covered in the capacitance code post.
Which disc capacitors offer no tolerance twin at all?
Every safety-certificated part and every Z5V part. We looked at the 46 rows with a Z letter. 28 of them have no M sibling because the whole Z5V dielectric is Z-only, 28 of 28, and none of the 367 safety-certificated rows carries a Z at all. The Y5V safety rows, 47 of them, are all M.
| Group | Rows | Letters present | Twin by letter | Real part | Match / mismatch |
|---|---|---|---|---|---|
| Z5V, general purpose | 28 | Z only | none | ZV500102Z050 |
Mismatch — no M version exists to cross to |
| Y5V, general purpose | 32 | M 16, Z 16 | 16 of 16 Z rows | YV101102M040, YV101102Z040 |
Match — every Z has an M twin |
| Y5V, safety certificated | 47 | M only | none | YV0AC103M140 |
Mismatch — Z does not exist on a safety part |
| Z5U, general purpose | 66 | M 64, Z 2 | 2 of 2 Z rows | ZU202222M070, ZU202222Z070 |
Match — but only at 1,000 and 2,000 Vdc |
The two Z5U twins are at one rated voltage each, 1,000 Vdc and 2,000 Vdc. At 50, 100, 500 and 3,000 Vdc there are 38 Z5U rows and no Z.
Does the Dielectric column tell you which tolerance a part has?
Only for four of seven dielectrics. We normalised the 11 spellings in the Dielectric column to 7 and counted the tolerances under each. YP, YU, Z5V and Y5R fix the tolerance, 476 rows, 51.2 percent. SL, Y5V and Z5U do not, 453 rows, 48.8 percent. The ambiguity sits inside three labels that look like selectors.
| Dielectric (normalised) | Rows | Tolerance letters | Does the label fix the tolerance? | Match / mismatch against a filter on Dielectric alone |
|---|---|---|---|---|
| YP (Y5P) | 258 | K | yes | Match |
| YU (Y5U) | 143 | M | yes | Match |
| ZV (Z5V) | 28 | Z | yes | Match |
| Y5R | 47 | K | yes | Match |
| SL | 308 | J 304, K 4 | no | Mismatch on 4 rows |
| YV (Y5V) | 79 | M 63, Z 16 | no | Mismatch on 16 rows |
| ZU (Z5U) | 66 | M 64, Z 2 | no | Mismatch on 2 rows |
A filter on dielectric alone for Y5V returns 79 parts, and 16 of them carry a tolerance a plus or minus 20 percent request would not accept. The 22 rows where the label misleads are exactly the 22 Z and K rows that have a twin. See disc capacitor temperature coefficient codes for what the dielectric labels themselves mean.
How should a buyer in Romania read a disc capacitor cross on tolerance?
Read the ninth character, then the tolerance string, then compare to your own band. Of 929 disc capacitors, 22 have a one-letter sibling, and a cross that lands on the wrong sibling widens the upper capacitance limit by up to 60 percentage points.
| Field | Walsin export, YV500103M060 |
Your incumbent part | Match / mismatch |
|---|---|---|---|
| Dielectric | Y5V | to be filled in | Compare the dielectric, which does not fix the tolerance |
| Capacitance | 0.01 uF printed, 10,000 pF | to be filled in | Compare the value, not the string |
| Tolerance | plus or minus 20 percent, letter M | to be filled in | Mismatch if yours is plus 80 minus 20, letter Z |
| Rated voltage | 50 Vdc | to be filled in | Compare the rating |
| Body code | 060 | to be filled in | Compare the footprint |
We hold 28 Walsin datasheets, 451 pages, none covering disc capacitors, so confirm against both datasheets and qualify in your own circuit. What is in Hong Kong is on ready stock, 1,125 part numbers as at 23 September 2026, a dated snapshot and not a live feed. Cross a disc capacitor with the free cross-reference tool, and see the range on the disc capacitor product page.
The short version
One letter changes the tolerance and 22 pairs of Walsin disc capacitors differ in nothing else: 18 pairs move plus or minus 20 percent to plus 80 minus 20 percent and 4 move plus or minus 5 percent to plus or minus 10 percent. A 10,000 pF part spans 8,000 to 12,000 pF at M and 8,000 to 18,000 pF at Z. 885 of 929 parts have no such sibling. Three dielectric labels, SL, Y5V and Z5U, cover 453 rows and do not fix the tolerance. We will not tell you a Z part stands in for an M part. We will show you the band. Qualification stays with you.
Send us the tolerance line off your drawing and we will tell you which letter it needs. A question back: when your last disc capacitor cross matched on dielectric, capacitance and voltage, did anyone check the ninth character?
Frequently asked questions
What does the ninth character of a Walsin disc capacitor part number mean?
It is the tolerance letter. J is plus or minus 5 percent on 304 rows, K is plus or minus 10 percent on 309, M is plus or minus 20 percent on 270 and Z is plus 80 minus 20 percent on 46. Each letter maps to one tolerance string on all 929 rows.
How many Walsin disc capacitors differ only in tolerance?
22 pairs, 44 rows of 929. In every pair the series, dielectric, capacitance, rated voltage and body code are identical. 18 pairs are M against Z and 4 are J against K. The other 885 parts have no sibling that differs by tolerance alone.
Is a plus 80 minus 20 percent Y5V disc capacitor a drop-in for a plus or minus 20 percent one?
Not without checking. The lower limit is the same, 8,000 picofarads on a 10,000 picofarad part, but the upper limit moves from 12,000 to 18,000 picofarads. We never call two parts interchangeable. Compare the band to what your circuit tolerates and qualify it.
Does a Walsin disc capacitor dielectric filter give me one tolerance?
Only for four of seven dielectrics: Y5P, Y5U, Z5V and Y5R. SL returns J on 304 rows and K on 4, Y5V returns M on 63 and Z on 16, and Z5U returns M on 64 and Z on 2. Filter on the tolerance letter as well.
Do safety-certificated Walsin disc capacitors come in plus 80 minus 20 percent?
No. None of the 367 safety-certificated rows carries a Z letter. The 47 Y5V safety rows are all plus or minus 20 percent, letter M. If you need a wider band the choice is in the general-purpose Class II range.
Does Venatech hold a datasheet for Walsin disc capacitors?
No. We hold 28 Walsin datasheets, 451 pages, covering 26 MLCC and 2 chip resistor series. Disc capacitors, varistors, inductors, thin film, radio frequency and antenna parts have none, so every figure here is from the export and should be confirmed with Walsin.