Chip Resistor Tolerance and Wattage Selection: 40 Files, Not 100, and 22 Return Nothing

Walsin’s high precision thick film chip resistor tolerance and wattage selection splits across exactly 40 export files, and 22 of them return zero rows. The split looks like one file per combination. It is not — two tolerances get fourteen files each while the rest share one bundled file. We globbed and opened all 40 ourselves.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds all 137 of Walsin Technology (Walsin)’s chip resistor export files. This post is measured from the 40 files matching High_Precision_Thick_Film_chip_resistor_*.xlsx, cross-checked against four sibling folders in the same directory — general purpose, anti-surge, high power and high voltage — to establish whether the naming pattern is specific to this line. Every part number below is real and every count is a count of files or part numbers, not pieces. We hold no datasheet covering any series in this shelf.

How many files actually match the high precision thick film glob?

Forty. We globbed the exact pattern High_Precision_Thick_Film_chip_resistor_*.xlsx against Walsin’s chip resistor directory and counted 40 files — not the roughly 100 a folder glance can suggest. We then opened every one of the 40 with pandas and counted rows: 18 return part numbers totalling 52,027, and 22 return exactly zero rows, a 55% empty rate for this specific product line’s own folder.

	Count
Files matching the glob	40
Files returning 0 rows	22
Files returning rows	18
Total part numbers across all 40	52,027

What does the file suffix grammar actually encode?

A tolerance code, optionally followed by a wattage code. We established this by cross-checking every filename’s suffix against the actual Tolerance and Rated Power columns inside that file, not by guessing from the text. 0_1 decodes to ±0.1%, 0_5 to ±0.5%, 0_25 to ±0.25%, 1 to ±1%, and the wattage half writes a fraction with an underscore in place of the slash — 1_10W is 1/10 W, 1_4W is 1/4 W, 3_4W is 3/4 W. High_Precision_Thick_Film_chip_resistor_0_1_1_4W.xlsx opens to 3,198 rows, every one ±0.1% tolerance and 1/4 W rated power, confirming the decode. Its sibling file 0_5_1_4W decodes the same way to ±0.5% at 1/4 W, and its first row is SF12H10R0DTL — a real part number, 10.0 Ω, Anti-Sulfuration series, 1206 — which checks out against both halves of the suffix.

Filename suffix	Decoded meaning	Rows	Tolerance in file	Wattage in file
0_1_1_4W	±0.1% tolerance, 1/4 W	3,198	±0.1%	1/4W
0_5_1_10W	±0.5% tolerance, 1/10 W	5,253	±0.5%	1/10W
0_25	±0.25% tolerance, no wattage code	5,369	±0.25%	four wattages in one file
1	±1% tolerance, no wattage code	7,514	±1%	five wattages in one file
Jumper	0 Ω zero-resistance link	0	—	—

Why do two tolerances get fourteen files each while most get one?

Because the folder mixes two different splitting rules for the same tolerance axis, and nothing in the filename tells you which rule applies until you open the file. We counted the files by tolerance token: 0_1 (±0.1%) and 0_5 (±0.5%) are each split into one file per wattage code — 14 wattage buckets apiece, 28 files total, of which 16 return rows. Every other tolerance token — 0_05, 0_10, 0_20, 0_25, 0_30, 1, 2, 5, 10, 20, 50 and Jumper — gets exactly one bundled file that holds every wattage at once, 12 files total, of which only 2 (0_25 and 1) return rows.

Splitting rule	Tolerance tokens	Files	Files with data
One file per wattage (14 wattage codes)	0_1, 0_5	28	16
One bundled file for all wattages	0_05, 0_10, 0_20, 0_25, 0_30, 1, 2, 5, 10, 20, 50, Jumper	12	2

So the two tolerances with the most parts in this shelf — ±0.1% and ±0.5%, together 30,529 of the 52,027 rows — are also the only two split finely enough to produce a near-empty file for every wattage that does not apply. The other four live tolerance-and-wattage combinations hide inside two single bundled files.

Is this naming pattern unique to the high precision line?

No. We checked four sibling folders in the same directory and found the identical 13-tolerance-token vocabulary — 0_05, 0_10, 0_20, 0_25, 0_30, plus 0_1/0_5 or 1 depending on the line, 2, 5, 10, 20, 50 and Jumper — reused across all of them, with the wattage-splitting rule changing from line to line.

Product line	Files	Tolerance split by wattage
High Precision Thick Film	40	0_1 and 0_5 (14 wattage files each)
Thick Film General Purpose	27	1 only (14 wattage files)
Thick Film High Power	30	1 only, plus two extra wattage codes
Thick Film Anti-Surge	14	none — every tolerance is one bundled file
Thick Film High Voltage	14	none — every tolerance is one bundled file

We have not seen this cross-folder comparison published anywhere. The 22 empty files in the high precision folder are not a defect specific to that line — 0_20, 0_30, 2, 5, 10, 20 and 50 are tolerance and current-handling codes that make sense for a general purpose or high power resistor and were never going to hold a high precision part. The folder reuses a shared export template across at least five product lines rather than generating a bespoke file list per line.

How many distinct tolerance-and-wattage combinations exist once the files are opened?

Twenty-five. We concatenated the 18 non-empty files and counted the distinct (Tolerance, Rated Power) pairs directly from the data, not from the file list. Eighteen live files produce 25 live combinations — not a 1:1 mapping — because the two bundled files (0_25 and 1) each hold several wattages at once.

Tolerance	Rated power values present	Count of distinct pairs
±0.1%	1/10W, 1/16W, 1/20W, 1/2W, 1/3W, 1/4W, 1/8W, 1W	8
±0.25%	1/10W, 1/16W, 1/4W, 1/8W	4
±0.5%	1/10W, 1/16W, 1/20W, 1/2W, 1/3W, 1/4W, 1/8W, 1W	8
±1%	1/10W, 1/16W, 1/20W, 1/4W, 1/8W	5

Counting files and counting selectable combinations give two different numbers on this shelf, 18 against 25, and a tool that reports “18 data files” is quietly undercounting what a buyer can actually ask for by seven combinations. The first row of the bundled 0_25 file is WF12K10R0CTL — TC50 series, 1206, 10.0 Ω, ±0.25% tolerance, ≦±50 ppm/°C, 1/4 W — and the first row of the bundled 1 file is WK12K3R30FTL, TC50, 1206, 3.30 Ω, ±1%, ≦±50 ppm/°C, 1/4 W. Both are real part numbers inside the two files a filename-only search would treat as a single tolerance each; both actually sit in the same TC50 series as WF12J1002BTL above, at a different tolerance.

What would a selector built from the file list alone get wrong?

It would offer six wattages Walsin never fills at any tolerance in this line, and a tolerance pair that is a near-duplicate of itself. We counted every wattage code that exists in a filename and checked it against the combined data: 1W, 2W, 3W, 1/2W, 1/3W, 2/3W, 2/5W, 3/4W and 1/32W all appear in at least one filename across the 40 files, but only 1W, 1/10W, 1/16W, 1/20W, 1/2W, 1/3W, 1/4W and 1/8W ever hold a row.

Worse, two filename tokens, 0_1 and 0_10, both plausibly decode to “0.10%” by the same underscore-for-decimal-point convention used everywhere else in the folder. Only 0_1 ever carries data — all of it reads as ±0.1% — and 0_10 is one of the 22 empty files. A reader who assumes the two tokens are duplicates of the same tolerance by design, rather than one live code and one template leftover, would not be wrong about the catalogue, only about why the folder lists both.

What should a buyer do with a shelf split this unevenly?

Search the data, not the file names. A buyer who filters by tolerance and wattage using the folder’s own naming scheme will miss the four combinations bundled inside 0_25 and 1, and will waste a lookup on 22 of the 40 files that were never going to return a part for this line. The trade press has reported passive component lead times stretching through 2026 as AI server and EV programmes draw on the same manufacturing capacity, so a sourcing team that loses time to an empty file is losing time it does not have.

1. Treat the file count and the combination count as two different numbers. This shelf has 18 live files and 25 live tolerance-and-wattage pairs; neither number is the other.
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. It decodes 18 manufacturers’ part numbers and matches against 800,000+ crossable Walsin part numbers, returning candidates field by field with every difference from your original stated rather than hidden.
3. Check what is physically in Hong Kong on ready stock before committing to a production slot. That page is a dated snapshot as at 23 September 2026, not a live feed.
4. Ask us for the series datasheet. We hold 28 Walsin datasheets, 451 pages, and none of them covers TC25, TC50, TC100, TC100 LF100ppm or High Precision Anti-Sulfuration. Your request is what puts the sheet on our list to Walsin.

Check us while you are here. UL file E182369 is searchable in UL’s own public database in about thirty seconds, and the TUV certificates we hold are named and numbered for the same reason.

For the full tolerance, TCR and wattage cube this shelf fills, see high precision thick film resistor shelf. For the trade-off against thin film construction, see thick film vs thin film precision resistor. The full range is on the Walsin chip resistor range page.

The short version

Walsin’s high precision thick film folder holds 40 files, not the roughly 100 a glance suggests, and we counted 22 of them returning zero rows. The suffix grammar encodes a tolerance code and an optional wattage code, but the splitting rule is inconsistent: 0_1 and 0_5 get one file per wattage while every other tolerance shares a single bundled file, and the same 13-token vocabulary recurs across at least four other Walsin chip resistor product lines. Counting files and counting live tolerance-and-wattage combinations give two different answers — 18 against 25 — because the bundled files each hide several combinations at once.

Send us your resistor requirement as tolerance, wattage and case size together and we will tell you which of the 25 real combinations it falls into, with Walsin part numbers, then tell you which of them was in Hong Kong on 23 September 2026.

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Frequently asked questions

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