High Precision Thick Film Resistor: 60 of 160 Tolerance, TCR and Wattage Cells Are Real

Walsin’s high precision thick film resistor shelf holds 52,027 part numbers in 18 of 40 export files, filling only 60 of 160 possible tolerance, TCR and wattage combinations. The other 100 are empty cells a careless selector would still offer. We globbed every file and counted every row 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, which we globbed and parsed in full rather than sampled. Every part number below is real and every count is a count of part numbers, not pieces. We hold no datasheet covering any of the seven series in this shelf — the only two chip resistor PDFs in our library are the MR automotive and WR general purpose sheets, and we checked both by text search for “TC25”, “TC50”, “TC100” and “Anti-Sulfuration”: none of the four strings appears in either file. Every tolerance, TCR and wattage figure below is the export’s own value.

How many high precision thick film files does Walsin’s export actually split into?

Forty, not the roughly one hundred a glance at the folder suggests. We globbed the exact pattern High_Precision_Thick_Film_chip_resistor_*.xlsx against Walsin’s chip resistor directory ourselves and counted 40 files. Eighteen return rows and 22 return nothing — 55% of this shelf’s own file structure is empty for this specific product line, and the parts sit in a shelf five times smaller than the file count implies.

	Count
Files matching the glob	40
Files returning 0 rows	22
Files returning rows	18
Total part numbers	52,027
Series represented	7
Case sizes represented	8 (0201 to 2512)
Tolerances represented	4 (±0.1%, ±0.25%, ±0.5%, ±1%)

How many of the 160 possible tolerance, TCR and wattage cells does the shelf fill?

Sixty of 160. The shelf carries 4 tolerances, 5 TCR grades and 8 rated-power values, which multiply out to 160 possible cells. We cross-tabulated all 52,027 rows on those three fields ourselves: 60 cells are occupied, 100 are empty, and four of the 60 hold exactly one part number each. All four single-part cells turn out to be the same part family at the same value — SF08H10R0BTL, SF10H10R0BTL, SF10H10R0DTL and SF12H10R0BTL, every one a 10.0 Ω High Precision Anti-Sulfuration part sitting at the resistance floor where thick film’s TCR collapses to its widest band, −200 to +400 ppm/°C.

Here is the tolerance-by-TCR slice of that cube, one layer with the wattage dimension collapsed:

Tolerance	−200～+400	≦±100	≦±200	≦±25	≦±50
±0.1%	5	9,587	1,142	1,029	4,340
±0.25%	0	0	0	1,029	4,340
±0.5%	580	12,984	1,712	1,029	6,736
±1%	0	547	0	0	6,967

We have not seen the 160-cell cube counted anywhere, and the shape of it tells a buyer something a flat series list does not: ±0.25% never reaches the wide bands and ±1% never reaches the tight ones, so tolerance and TCR are not independent axes on this shelf — picking one narrows the other before you have opened a single datasheet.

Which case sizes reach the tightest TCR grade in this shelf?

Three of eight. We grouped all 52,027 rows by case size and TCR and found that only 0603, 0805 and 1206 ever reach ≦±25 ppm/°C, this shelf’s tightest grade. 0201 and 0402 cap at ≦±50, and 1210, 2010 and 2512 cap at ≦±100 — the three largest case sizes in the shelf never see the two tightest TCR bands at all.

Size	−200～+400	≦±100	≦±200	≦±25	≦±50
0201(0603)	0	296	2,284	0	686
0402(1005)	117	4,336	114	0	4,570
0603(1608)	117	4,450	114	1,029	5,482
0805(2012)	117	3,994	114	1,029	5,707
1206(3216)	117	3,994	114	1,029	5,938
1210(3225)	117	2,852	114	0	0
2010(5025)	0	1,598	0	0	0
2512(6432)	0	1,598	0	0	0

Does a case size get a free choice of rated power?

No. We cross-tabulated case size against rated power across the full shelf and found that seven of the eight case sizes draw from a single dominant wattage, not a menu. 1206 is 1/4 W on all 11,192 of its rows. 2512 is 1 W on all 1,598. 0201 is 1/20 W on all 3,266. Only 0402 and 0603 split across two wattages each, and even there the split tracks series rather than customer choice.

Size	1/10W	1/16W	1/20W	1/2W	1/3W	1/4W	1/8W	1W
0201(0603)	0	0	3,266	0	0	0	0	0
0402(1005)	1,941	7,196	0	0	0	0	0	0
0603(1608)	10,393	0	0	0	0	0	799	0
0805(2012)	0	0	0	0	0	799	10,162	0
1206(3216)	0	0	0	0	0	11,192	0	0
1210(3225)	0	0	0	1,941	1,142	0	0	0
2010(5025)	0	0	0	1,598	0	0	0	0
2512(6432)	0	0	0	0	0	0	0	1,598

Rated power behaves like a derived field here, not a selector. Filter by case size first and the wattage is already decided for you on six of the eight sizes.

Which single series carries the most parts, and how deep is it?

TC50, with 14,797 of the shelf’s 52,027 rows — 28.4%, more than the four smallest series combined. We counted all seven series directly from the concatenated export.

Series	Rows	Share of 52,027
TC50	14,797	28.4%
TC100	11,190	21.5%
TC50 (Automotive)	8,680	16.7%
High Precision Anti-Sulfuration	5,710	11.0%
TC100 LF100ppm	4,568	8.8%
TC100 (Automotive)	3,995	7.7%
TC25	3,087	5.9%

TC50 and its automotive variant together account for 23,477 rows — 45% of the whole shelf sitting in two of the seven series. TC25, the series with the tightest TCR name in the shelf, is also the smallest: 3,087 rows, 5.9% of the total.

What does one real 10 kilohm requirement return from this shelf?

Twenty candidates, one exact match. We filtered the full export to the 1206 case size at exactly 10,000 Ω and counted 20 part numbers spanning all four tolerances and four of the five TCR grades. Against a requirement of ±0.1% tolerance, ≦±25 ppm/°C TCR and 1/4 W, only one part lands on all three fields at once.

Part number	Series	Tolerance	TCR	Rated power	Match / mismatch vs ±0.1%, ≦±25, 1/4W
WF12J1002BTL	TC25	±0.1%	≦±25	1/4W	Match on all three fields — the only exact hit of the 20
WF12K1002BTL	TC50	±0.1%	≦±50	1/4W	Match on tolerance and power; mismatch — TCR 2× looser
WF12H1002BTL	TC100	±0.1%	≦±100	1/4W	Match on tolerance and power; mismatch — TCR 4× looser
SF12H1002BTL	High Precision Anti-Sulfuration	±0.1%	≦±100	1/4W	Match on tolerance and power; mismatch on TCR, adds sulfur resistance
WF12K1002BTLJ	TC50 (Automotive)	±0.1%	≦±50	1/4W	Match on tolerance and power; mismatch on TCR, adds automotive grade
WK12K1002DTL	TC50	±0.5%	≦±50	1/4W	Mismatch on tolerance and TCR — the WK prefix sits in the same TC50 series as the WF rows above
MF12H1002DTL	TC100 (Automotive)	±0.5%	≦±100	1/4W	Mismatch on tolerance and TCR
WF12K1002FTLJ	TC50 (Automotive)	±1%	≦±50	1/4W	Mismatch — the loosest candidate at this exact value

Nineteen of the 20 candidates match on resistance and footprint and differ somewhere a resistance-only filter will not show side by side. We will not tell you a part is equivalent. We will show you where it differs — confirm against the datasheet you request and qualify in your own circuit.

What should a buyer do with a shelf this fragmented?

Fix the cell, not the resistance, before you open a single file. A 10 kΩ 1206 requirement at ±0.1% and ≦±25 ppm/°C has one exact answer in a shelf of 52,027 rows, and the other 19 candidates at the same value will pass a resistance-only filter and fail on TCR or tolerance. The trade press has reported MLCC and passive component lead times stretching through 2026 as AI server and EV programmes draw on the same capacity, so the practical question is not just which cell is correct — it is which part is sitting in a warehouse.

1. State tolerance, TCR and wattage together, not resistance alone. This shelf has 60 live cells out of 160; most requirements fall in one of them, and knowing which one before you search saves a quote-stage surprise.
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 how this shelf compares with Walsin’s thin film precision line field by field, see high precision thick film vs thin film precision. For the construction difference behind both shelves, see thin film vs thick film chip resistors. The full range is on the Walsin chip resistor range page.

The short version

Walsin’s high precision thick film shelf is 40 files, not the roughly 100 a quick folder glance implies, and 22 of those 40 return zero rows. The 18 live files hold 52,027 part numbers across seven series, filling 60 of 160 possible tolerance, TCR and wattage cells. Only three case sizes — 0603, 0805 and 1206 — ever reach the tightest TCR grade, and rated power tracks case size rather than offering a free choice on six of the eight sizes. One real 10 kΩ, 1206 requirement returns 20 candidates and exactly one exact match.

Send us the tolerance, TCR, wattage and case size your circuit actually needs and we will come back with every Walsin candidate in that cell, mismatches stated plainly, 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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