Chip Resistor Tolerance and TCR by Series for Hong Kong Buyers: 28 of 81 Pairs Exist in One Series Only

Chip resistor tolerance and TCR by series is a narrower choice than the grid suggests. We counted 81 distinct tolerance and TCR pairs across 58 Walsin series strings. 28 of the 81 exist in exactly one series, so for 34.6 percent of pairs, choosing the pair has already chosen the series.

Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the chip resistor parametric exports published by Walsin Technology (Walsin). This post is written from those files, read through Walsin_ChipR_Product_Data (for example Thick_Film_General_Purpose_1_1_4W.xlsx): 64 of the 137 hold rows, carrying 234,815 part numbers. Every part number below is real and every count is of part numbers, not pieces. Earlier posts counted the tolerance and TCR grid by series group. This one cuts it by series, which is the unit a second-source decision actually turns on.

How many tolerance and TCR pairs does each Walsin chip resistor series offer?

Between 1 and 20, with a median of 4. We grouped all 234,793 rows by series, tolerance and TCR, after setting aside the 22 chip attenuator rows that write ohms into the tolerance field and decibels into the TCR field. That leaves 81 distinct pairs across 58 series strings. The widest series, Thick Film Low Ohm Current Sense Chip-Resistor, offers 20 pairs. The narrowest resistive series offer 2, and the attenuator series holds a single jumper row.

The mean is 5.8 pairs per series.

How many pairs exist in only one series?

28 of 81, which is 34.6 percent. We counted the number of series strings behind every pair. 28 pairs sit in one series, 25 in two, 10 in three, 5 in four, and the rest spread up to the commonest pair, plus or minus 5 percent with a TCR of plus or minus 200 ppm or less, which appears under 38 series strings. 53 pairs therefore have a second series to look at, and 28 have three or more.

We have not seen this counted anywhere. The 28 single-series pairs hold 16,452 rows, 7.0 percent of the 234,793. The shelf is thin in rows too: the median pair holds 276 rows, and the smallest holds 1. That one row is a zero-ohm jumper, WF10P000 PTL, which writes a TCR of plus or minus 100 on a part with no resistance to drift. The other 125 jumper rows write a dash. So 27 of the 28 are genuine tolerance pairs and the twenty-eighth is a formatting difference.

Which ten series own the 28 single-series pairs?

Ten, and one of them owns eight. We listed every single-series pair against its owner. Trimmable owns eight, Anti-Surge four, General Purpose LF 100ppm four, High Precision TC25 three, High Voltage (Automotive) three, Wide Terminal Power Low Ohm two, and four more series own one each.

Read the TC25 row against the requirement in its header. Plus or minus 0.5 percent at 25 ppm or better exists in exactly one series, TC25, where WF06J4700DTL is one of 1,029 rows. A buyer who needs that pair cannot have a second Walsin series. The thin film side is in precision thin film tolerance and TCR, and the shape of the thick film grid is in chip resistor tolerance and TCR for Netherlands buyers.

Which pairs exist only in series named Automotive?

Five. We split every series string by whether the word Automotive appears in it. 5 of the 81 pairs have no row in any other series: plus or minus 2 percent at 100, 200 and minus 200 to plus 500 ppm, and plus or minus 1 percent and plus or minus 5 percent at minus 100 to plus 350 ppm. 37 pairs appear in no Automotive-named series at all, and 39 appear in both.

The word is in Walsin’s series name. It is not an AEC-Q200 claim. Walsin’s wording is compliant, never certified, and a qualification report is not in the documents we hold. Ask for the report for the exact part. Our automotive split covers the suffix side.

Is the series name a reliable thing to count?

No, and the count moves when you normalise it. We lower-cased every series string and collapsed repeated spaces: 58 strings become 55. Three convex array series each appear twice, once as Convex Type and once as Convex type. The pair count stays at 81 and the single-series count at 28, but three pairs change their series tally: plus or minus 5 percent at 200 ppm falls from 38 strings to 35, plus or minus 1 percent at 200 ppm from 35 to 33, and the jumper dash from 28 to 25.

Separately, one power surge series is spelled Thick Flim in the export, on 3,030 rows. A filter on the correct word returns none of them.

What should a Hong Kong BOM filter do with a pair that lives in one series?

Treat the pair as a series requirement and say so. For 28 pairs the answer to “who else makes this” inside Walsin is nobody else in the export. We hold 28 Walsin datasheets, 451 pages, and only two cover chip resistors, Walsin_WR_General_Purpose_Chip_Resistor.pdf (ASC_WR_V24, September 2016) and Walsin_MR_Automotive_Thick_Film_Chip_Resistor.pdf (ASC_MR_V13, March 2024); for Anti-Surge, Trimmable, High Precision and High Voltage we hold no datasheet, so tolerance and TCR in those series are the export’s values and should be confirmed with Walsin. The free cross-reference tool shows differences from your incumbent instead of hiding them, and ready stock lists 1,125 part numbers as at 23 September 2026, a dated snapshot. The range sits on the chip resistor page.

The short version

We parsed all 234,793 resistive and jumper rows in the 64 non-empty Walsin chip resistor files. 81 tolerance and TCR pairs exist across 58 series strings, 55 once case and spacing are normalised. 28 pairs sit in one series, 16,452 rows, and one of the 28 is a jumper. 5 pairs exist only in series named Automotive. Pick the pair and you have often picked the series. Confirm against both datasheets and qualify in your own circuit.

Send us the tolerance and TCR line off your drawing and we will tell you how many series carry it. And a question back: when your approved vendor list names one precision resistor series, does the list know the pair lives in one series?

Frequently asked questions