Capacitors get the attention because of their sheer count, but resistors and inductors make up the rest of the passive bill of materials, and they follow a logic that is easier to read. In both families a small number of manufacturing processes map onto a small number of performance tiers. The tier an application needs decides which process is economically justified, and the cheap tier wins on volume almost everywhere. Precision and power-handling tiers win where the circuit leaves no cheaper option.
In this piece I go through the technology families in each class, explain where each one is used, and then turn to the Indian side: who is expanding passive capacity under the Scheme for Promotion of Components and Semiconductors (SPECS), what Dixon Technologies tells us about demand, and where the evidence stops.
Why passives dominate the board
Passives have no transistor, no gate and no firmware to update. A resistor resists, a capacitor stores, an inductor opposes a change in current, by virtue of its physical construction. That simplicity is why they dominate by count. Industry tallies place capacitors, resistors and inductors together at somewhere between 70% and more than 80% of total component count on a modern printed circuit board assembly, depending on the source and the product category.
The common thread across resistors and inductors, and across capacitors as well, is that the process is chosen to fit the specification. A designer does not pick a thin-film resistor or a wire-wound RF inductor because it is more sophisticated in the abstract. The tolerance, drift or Q-factor budget of the circuit leaves no cheaper part that still closes the design margin. That discipline is why the low-cost tiers stay the overwhelming majority of unit volume even as the precision tiers capture the applications where performance is the binding constraint.
Resistors: thick film, thin film and current sense
Thick film: the volume workhorse
Thick-film chip resistors are made by screen-printing a ruthenium oxide (RuO2) paste onto a ceramic substrate. It is a comparatively low-cost, high-throughput process, and it dominates general-purpose surface-mount applications across consumer and industrial electronics. If a board has a pull-up resistor or a bias divider with no special accuracy requirement, this is the part that sits there.
Thin film: when measurement is the product
Thin-film resistors deposit a nichrome (NiCr) or tantalum nitride (TaN) resistive layer by vacuum sputtering, a physical vapour deposition process. It is slower and more capital-intensive, and it buys much tighter tolerance, down to plus or minus 0.01%, and a much lower temperature coefficient of resistance, on the order of 5 parts per million per °C. That precision is what mandates thin film wherever measurement accuracy is itself the requirement: precision medical instrumentation, automotive sensing and aerospace metering circuits, none of which can tolerate the wider drift of a thick-film part.
Current-sense: the electrification resistor
A third category has become consequential with vehicle electrification. Current-sense resistors are built as low-resistance metal strips rather than printed films. A battery-management system measures current directly by sensing the small voltage drop across a precisely known, ultra-low resistance. Every lithium-ion pack in an EV or grid-scale storage system relies on this class of part for state-of-charge estimation and overcurrent protection. As EV and storage volumes scale, this has become one of the faster-growing resistor sub-segments.
Inductors: powder cores for current, wire wound for signal
Inductors split along a similar performance-versus-cost axis, though the physics is magnetic rather than resistive. Two applications show the divide well.
Power inductors
Power inductors sit in the multi-phase buck converters that step down and regulate supply voltage for AI accelerator GPUs and high-performance CPUs. They are built by moulding a metal alloy powder core, typically a Sendust (iron-silica-aluminium) formulation, chosen for high saturation current (Isat) and low DC resistance (DCR). As accelerator power draw climbs into the hundreds of watts per package, the current-handling and low-loss demands on these parts climb with it.
RF inductors
RF inductors in 5G front-ends prioritise signal quality over raw current handling. They use high-precision wire-wound construction on an alumina ceramic core, engineered for a high quality factor, typically Q greater than 50 at 1 GHz, across the sub-6GHz and mmWave bands that carry the radio signal.
| Component class | Process | Core / resistive material | Key metric |
|---|---|---|---|
| Power inductors | Metal alloy powder molding | Iron-silica-aluminium (Sendust) | High saturation current, low DCR |
| RF wire-wound inductors | Precision wire winding | Alumina ceramic core | Q above 50 at 1 GHz |
| Thin-film resistors | Vacuum sputtering (PVD) | NiCr or TaN | ±0.01%, about 5 ppm/°C |
| Thick-film resistors | Screen printing on ceramic | RuO2 paste | Low cost, general purpose |
Where demand is shifting
Two shifts favour the higher tiers. Battery-management systems in EVs and grid storage need current-sense resistors at a scale that a decade ago belonged to niche automotive and industrial use. Multi-phase power delivery for AI accelerators needs power inductors rated for current and switching-loss envelopes that consumer electronics never asked for.
Neither shift displaces thick-film resistors or standard moulded inductors as the highest-unit-volume products. General-purpose SMT assembly still consumes far more of both than any precision application. But the fastest-growing revenue pools within resistors and inductors sit disproportionately in the specialised segments, and those are also the more concentrated ones. I would keep that distinction in mind when anyone quotes a single growth number for "passives".
How concentrated is the supply?
For MLCCs the concentration is stark, and I set it out in the MLCC article. For resistors and inductors it is somewhat less acute. Thick-film resistor and moulded-powder inductor manufacturing is more geographically distributed, and the materials, RuO2 paste and Sendust powder, are less exotic than battery-grade barium titanate.
The precision tiers are different. Thin-film NiCr and TaN resistors and high-Q wire-wound RF inductors still cluster among a comparatively narrow set of specialist suppliers. The reason is the same one that explains MLCC miniaturisation: process know-how compounds with cumulative volume, and a smaller number of firms have run that volume for longer than everyone else. A buyer who assumes all passives are equally easy to re-source will be wrong exactly where the design is most demanding.
| Tier | Examples | Unit volume | Supplier concentration |
|---|---|---|---|
| General purpose | Thick-film chip resistors, moulded power inductors | Overwhelming majority | More distributed |
| Precision and specialist | Thin-film NiCr/TaN resistors, wire-wound RF inductors | Smaller share | Narrow set of specialists |
| Electrification-driven | Current-sense resistors, AI-grade power inductors | Growing fastest | Specialised, more concentrated |
India's passive base and SPECS
India's passive-component industry starts from heavy historical reliance on imports from China, Taiwan and Japan. Under SPECS, companies including Vishay Components India, Syrma SGS and CDIL are named as expanding passive-component production capacity within India, which is a direct policy response to that dependence. The book is careful about what it does not know. What share of India's domestic passive demand those expansions will cover is an open data point, pending a clearer MeitY component-survey disclosure. I would not attach a percentage to it, and I do not think anyone else should either without a source.
The shape of the gap is easier to state than its size. On one side sits a very large assembly base. On the other sit a handful of named specialists building capacity. Between them is the question of whether local supply reaches the volumes and, at the top of the value chain, the process depth that large-scale assembly needs.
What Dixon tells us, and what it does not
Dixon is a useful lens on demand, not on supply. It reported becoming India's largest smartphone manufacturer by shipments in the quarter ending mid-2025, with over 22% market share, and is reported to hold more than 35% of the LED TV outsourcing market, alongside appliances, LED lighting and a newer laptop and IT-hardware line for HP, Lenovo, Acer and Asus. Its footprint includes Noida, the Tirupati and Chittoor district of Andhra Pradesh, Dehradun, Chennai's Oragadam cluster and a further plant announced in Karnataka. Sources cite 17 to 24 active manufacturing units. The book reads that discrepancy as new plants coming online through 2025 and 2026 and flags the current authoritative count as still requiring evidence.
At those volumes, a single LED TV or smartphone run translates into passive demand in the tens of millions of units a year. Dixon's disclosed backward integration, however, points at camera modules (a 51% stake in Q Tech India), an optical-transceiver joint venture with Taiwan's Gemtek and a wearables joint venture with boAt Lifestyle, not at MLCCs, resistors or inductors. The revised PLI structure rewards local component manufacturing over pure assembly, which gives an EMS major a reason to move up the chain. It does not show that Dixon itself is becoming a passive-component maker. Vishay Components India, Syrma SGS and CDIL remain the entities actually building passive capacity, and Dixon and its peers are the demand pool that capacity would need to serve.
Assembly scale is not the same as component scale. India has the first and is building the second, and the deepest tier of the passive supply chain is, on the available evidence, still a gap.
Four boards, four choices
The clearest way to see the tier logic is to walk through four products and ask which passive families each one needs. This is my own illustration built on the applications the book names, not additional data.
A consumer LED TV or smartphone board
Most of the resistors are thick-film chip parts, because nothing on the board needs accuracy beyond what a printed ruthenium oxide film delivers cheaply. Most inductors are moulded powder types. The capacitors are overwhelmingly Class 2 MLCCs. The volume is enormous and the price per part is small, so this is where cost and throughput decide everything. It is also the board type that an EMS major such as Dixon assembles in the largest quantities.
An EV battery-management system
Here the current-sense resistor is the critical component. The BMS measures pack current through the voltage drop across a known ultra-low resistance, and state-of-charge estimation and overcurrent protection both depend on that measurement. A thick-film part would not be the natural choice for a measurement this important, so the design leans on the low-resistance metal-strip construction the book describes. The same board still contains thick-film resistors elsewhere. The tiers coexist on one PCB.
An AI accelerator power stage
The multi-phase buck converters that regulate supply voltage for an accelerator use power inductors with a moulded Sendust core, selected for saturation current and low DC resistance. As package power climbs into the hundreds of watts, the inductor's current handling and losses become a limiting factor for the power stage as a whole. That is a very different requirement from a consumer board, even though the part is, at first glance, the same kind of component.
A 5G radio front-end
Signal quality matters more than raw current. The inductors here are high-precision wire-wound parts on alumina ceramic cores, engineered for Q above 50 at 1 GHz. Precision resistors and Class 1 capacitors appear where drift itself would be the failure mode. The board is small, but almost every passive on it is a specified choice, not a default.
The same PCB can hold parts from every tier. What changes from board to board is the share of the bill of materials that sits in the precision or high-current tier.
Why the precision tiers resist commoditisation
There is a reasonable question underneath all this: if thick-film and moulded-powder parts are widely made, why do the precision tiers stay concentrated? The book's answer, which I find persuasive, is about process rather than materials. A sputtered NiCr or TaN film held to plus or minus 0.01% and about 5 ppm/°C is the outcome of a slower, more capital-intensive deposition process that has to be controlled tightly over long runs. A wire-wound RF inductor with a Q above 50 at 1 GHz is a matter of winding precision and core quality. Neither is exotic in its raw materials. Both take accumulated experience to do consistently at volume.
That has a procurement consequence. When a design depends on a thin-film resistor for measurement accuracy, a substitute has to meet the same tolerance and drift limits, and a wire-wound inductor has to meet the same Q at the same frequency. The pool of parts that can do that is smaller than the pool of generic parts, which is why supply risk is not uniform across the passive family.
Reading the evidence on India carefully
I would separate India's passive story into what is known, what is inferred and what is open, because the temptation with a policy-backed sector is to blur them.
- Known. Historical reliance on imports from China, Taiwan and Japan. SPECS names Vishay Components India, Syrma SGS and CDIL as expanding passive-component production capacity in India. Dixon is a very large EMS/ODM player with a wide manufacturing footprint.
- Inferred. Because passives account for most of the component count on a board, high-volume assembly implies very large passive demand, in the tens of millions of units for a single product line at Dixon's scale, sourced mainly from the East Asian base.
- Open. What share of domestic passive demand SPECS-backed expansion will cover. The current authoritative count of Dixon's manufacturing units. Any confirmed India-based capability in barium titanate powder synthesis, which is the deepest tier of the MLCC chain.
The point of separating them is that policy announcements tend to describe capacity in future tense, while assembly volumes are already in the present tense. The gap between the two is where I would watch, and it can only be measured once the MeitY component-survey data the book is waiting for is available.
Which passive is most exposed?
Based on the book's own logic, India's exposure is not the same across the three families. MLCCs are the most concentrated globally and depend on powder chemistry that India has not shown to exist domestically. Thick-film resistors and moulded inductors are more geographically distributed and use less exotic materials, so local capacity there is a more attainable first step. The precision tiers sit in between: narrow global supply, but with process know-how that can, in principle, be built with the right partners. That ordering is my inference from the book's structure, not a sourced ranking, and I flag it as such.
Questions I would ask of any localisation claim
- Which tier of passive is being localised: general-purpose, precision or electrification-driven?
- Is the claim about assembly of imported elements, or about manufacturing from materials?
- What share of a named customer's demand does the capacity serve?
- Where does the powder or paste, RuO2, Sendust or BaTiO3, come from?
These are simple questions, and the book's evidence does not answer all of them. That is fine. Asking them is how one avoids mistaking capacity announcements for capability.
What to take away
Resistors and inductors are best read as tiered markets. Thick-film resistors and moulded Sendust-powder inductors carry the volume. Thin-film NiCr and TaN resistors and wire-wound alumina-core RF inductors serve the smaller share of applications where tolerance or Q-factor decides the design.
The growth is skewed towards the specialised tiers, driven by battery management and AI power delivery, and those tiers are also the more concentrated. So the supply risk is not spread evenly across the passive family.
For India, SPECS-backed expansion at Vishay Components India, Syrma SGS and CDIL is real, and EMS demand from players like Dixon is large and growing. The size of the coverage gap, and any domestic capability at the materials layer, are open questions. I would rather leave them open than fill them with numbers that do not exist.