Heat pump inverter electronics in Wroclaw, Poland, that choose a high voltage chip resistor for a divider leg cannot see the difference in the Walsin Technology (Walsin) export: 13,690 of the 20,244 High Voltage rows (67.6 percent) share size, value, tolerance and rated power with a General Purpose row, and none is on our shelf.
Venatech Limited, an authorised Walsin distributor in Hong Kong, wrote this from the Walsin chip resistor exports (234,707 rows, 234,294 distinct part numbers, jumper files excluded), one Walsin resistor datasheet and our stock list as at 23 September 2026. It is for a design engineer at a heat pump drive or controller maker around Wroclaw who is sizing a high-voltage sense divider. Every part number is real and every count is ours. The market statement names its source and the day we fetched it, 10 November 2026.
What did Aira report about its Wroclaw heat pump factory?
It reported a factory it plans to double. According to the Invest in Wroclaw agency on 19 August 2025, Aira raised 150 million euros, mostly for expanding its Wroclaw plant from about 250,000 to 500,000 heat pumps a year, on a former Volvo Buses site, with about 200 people employed at the time.
The same page says the original investment was 1.27 billion zloty and that production started nine months after the decision. It gives no completion date for the expansion. That is the agency’s report, not our figure. We have no relationship with Aira or any other heat pump maker and say nothing about what they buy.
How many chip resistors does a 400 V DC link divider need?
More than the voltage alone suggests, because the datasheet limit is per part. The Walsin WR general purpose datasheet we hold (ASC_WR_V24, September 2016) prints a maximum operating voltage of 200 V for a 1206, 150 V for a 0805, 75 V for a 0603 and 50 V for a 0402, so a 400 V link needs at least 2, 3, 6 or 8 parts in series.
That is our arithmetic on an assumed 400 V DC link, a value for you to replace with your own. It uses the sheet’s limit as the whole budget. Applying a working-voltage derating of 70 percent, which is an assumed design rule and not Walsin’s, the counts become 3 in 1206, 4 in 0805, 8 in 0603 and 12 in 0402. The sheet is ten years old and covers the WR family only. Our post on chip resistor power rating by case size covers the power side of the same question.
What does the Walsin High Voltage series add that the export can show?
Less than its name implies. We matched each of the 20,244 High Voltage rows against the 75,554 General Purpose rows on size, resistance, tolerance and rated power: 13,690 match, 11,773 of them also on temperature coefficient, and for plus or minus 1 percent the figure is 11,425 of 11,497.
The 6,554 rows with no General Purpose twin are mostly in tolerances the General Purpose group does not list: 3,045 at plus or minus 0.5 percent and 3,045 at plus or minus 2 percent, plus 392 at plus or minus 5 percent and 72 at plus or minus 1 percent. The export has no working-voltage column, and we hold no datasheet for this series, so the one field that would separate a High Voltage part from its twin is the field you cannot read. The series splits into four labels: standard 10,437, automotive 6,803, UL safety certification 1,502 and UL safety certification automotive 1,502. Ask for the datasheet of the exact part before relying on a voltage.
Which Walsin parts answer a 1206, 330 kilohm, 1 percent divider-leg brief, and what differs?
Four parts match on every field the export carries, and the export cannot rank them. For a 1206, 330 kilohm, plus or minus 1 percent, 100 ppm, one quarter watt brief, the export returns WK12V3303FTL, WF12N3303FTL, WR12X3303FTL and MR12X3303FTL with identical electrical fields, and none of the four is on our shelf.
| Walsin part | Series | Value / tolerance / TCR / power | On shelf 23 Sep 2026 | Match / mismatch with the brief | Your incumbent |
|---|---|---|---|---|---|
WK12V3303FTL |
High Voltage | 330 kilohm, plus or minus 1%, 100 ppm, 1/4 W | No | Match on every export field; working voltage not in the export | |
WF12N3303FTL |
High Voltage, UL safety certification | same | No | Match on every export field; series carries a UL label we cannot verify from the export | |
WR12X3303FTL |
General Purpose | same | No | Match on every export field; the WR sheet prints 200 V maximum operating voltage at 1206 | |
MR12X3303FTL |
General Purpose, automotive | same | No | Match on every export field; automotive series, mismatch if you do not want one | |
WR12X2203FTL |
General Purpose | 220 kilohm, plus or minus 1%, 100 ppm, 1/4 W | Yes | Mismatch: value is 220 kilohm, not 330 |
A match in the table is a match on the export fields and no more. Confirm against both datasheets and qualify in your own circuit. Our post on anti-surge chip resistors covers the other series that look alike in an export.
What does the Hong Kong shelf hold for a divider leg?
General Purpose lines only. None of the 20,244 High Voltage rows is on our stock list as at 23 September 2026; between 100 kilohm and 1 megohm at plus or minus 1 percent the shelf holds 22 General Purpose lines: 8 in 0603, 8 in 0402, 5 in 1206 and 1 in 0805.
The 1206 lines are WR12X1003FTL (100 kilohm), WR12X1503FTL, WR12X2203FTL, WR12X4993FTL and WR12X6803FTL. The shelf is 1,125 distinct part numbers in all, which we re-counted. The ready stock list is a dated snapshot and never live-synced, and the chip resistor range lists the families. A High Voltage series part is a to-order enquiry, and we give no lead time or price.
What will we not tell you about heat pump makers?
Anything about their drive design, safety approvals or purchasing. Of the 28 Walsin datasheets we hold, 2 cover chip resistors (MR and WR), and neither covers the High Voltage series, so every High Voltage count here is catalogue coverage and not a voltage specification.
We make no claim that any part meets an insulation, creepage or safety requirement, and we do not know what any named company’s drives contain. We hold no office, entity or stock in Poland; our locations are Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation. We hold no ISO 9001 or IATF 16949 certificate. We give no legal, customs or conformity advice; confirm with your compliance team.
How can Venatech help a Wroclaw heat pump electronics buyer?
How Venatech helps starts with a free paste box. The cross-reference tool, VenaMatch, decodes 18 manufacturers’ part numbers across 800,000+ crossable parts, takes up to 500 part numbers or an Excel or CSV file, and marks each field of a Walsin candidate as match or mismatch. Load a whole BOM for review. The ready-stock list is a Hong Kong snapshot dated 23 September 2026.
Worked example from our own exports: a 1206, 330 kilohm, 1 percent divider brief returned four identical-field matches across four series labels, and the only stocked neighbour was a different value. Walsin is the only line we are authorised for. Stackpole and Viking are lines we supply. We serve from Hong Kong in small lots, we help cross-reference, and you request a quote through the site.
The short version
For a Wroclaw drive, treat the High Voltage label as a question to put to the datasheet, not an answer in the export: two thirds of its rows are field-for-field the same as a General Purpose part. Work out the series count from the working voltage first.
Send us one divider line from your BOM, with the working voltage you must meet, and we will return the Walsin parts with every difference stated. If voltage is the constraint, which can move: the case size or the number of parts in series?
Sources
Fetched 10 November 2026.
- Invest in Wroclaw, “A Swedish company has secured 150 million euros, will expand its heat pump factory in Wroclaw”, 19 August 2025: https://invest-in-wroclaw.pl/aira-swedish-company-has-secured-millions-euro-will-expand-heat-pump-factory-in-wroclaw
- Walsin WR General Purpose Chip Resistor approval sheet, ASC_WR_V24, September 2016 (held by Venatech; no public URL held, so check Walsin’s site for the current sheet).
Related reading
- Chip resistor power rating by case size
- Anti-surge chip resistors
- Low-ohm current sense: thick film versus metal
- Free tools: VenaMatch cross reference and the ready stock list
Last reviewed 10 Nov 2026.
Frequently asked questions
What did Invest in Wroclaw report about Aira?
On 19 August 2025 it reported that Aira raised 150 million euros, mostly to expand its Wroclaw heat pump plant from about 250,000 to 500,000 units a year, with about 200 people employed. It gave no completion date. These are the agency’s statements.
What is the maximum operating voltage of a Walsin 1206 general purpose resistor?
200 V, DC or RMS, on the WR datasheet ASC_WR_V24 dated September 2016. The same sheet gives 150 V for 0805, 75 V for 0603 and 50 V for 0402. It is ten years old, so check Walsin’s current sheet.
How many 1206 resistors does a 400 V divider need?
At the sheet limit, 2. With a 70 percent derating, which is an assumed design rule, 3. The 400 V link is also our assumed example. Use your own link voltage and rule, and confirm with your design review.
Is a Walsin High Voltage chip resistor different from a General Purpose one in the export?
Not in the fields it carries. 13,690 of 20,244 High Voltage rows match a General Purpose row on size, value, tolerance and rated power. The export has no voltage column, so request the datasheet for the exact part.
Is any Walsin High Voltage chip resistor on the Hong Kong shelf?
No. None of the 20,244 rows is on our stock list as at 23 September 2026. The shelf holds 22 General Purpose lines between 100 kilohm and 1 megohm at plus or minus 1 percent. The snapshot is dated, not live.
Do you hold stock or an office in Poland?
No. We hold no office, entity or stock in Poland; our locations are Hong Kong, Shenzhen, Singapore and Jiangmen. We hold no ISO 9001 or IATF 16949 certificate and give no legal, customs or conformity advice. Confirm with your compliance team.