Every capacitor is two conductors separated by an insulator, and the insulator — the dielectric — decides nearly everything: how much capacitance fits in a cubic millimetre, how stable the value stays with temperature and voltage, whether the part is polarized, and how it eventually fails. Five families cover almost every component you will ever buy: ceramic capacitors are the tiny, cheap, non-polarized workhorses of decoupling; aluminum electrolytics own the bulk-storage range; film capacitors trade size for precision, stability and self-healing; tantalums pack microfarads into small polarized cases; supercapacitors reach whole farads for backup energy. Below, each family gets a deep dive — structure, parameter ranges, pros, cons and failure mode — followed by a comparison table, a ceramic-vs-electrolytic verdict and a selection decision path.
Component catalogs do not sort thousands of parts by value alone; they sort by family, because the family predicts behavior better than any single number can. Four classification axes cover the whole field — and knowing which axis a datasheet line belongs to is half of reading it.
By dielectric material
This is the axis engineers actually mean when they say a part is “ceramic”, “film” or “electrolytic”. The dielectric sets the dielectric constant K, and K spans three orders of magnitude across families — about 2.2 for polypropylene film, 8.4 for aluminum oxide, around 27 for tantalum pentoxide, and from the thousands into the tens of thousands for barium-titanate Class 2 ceramics. Because C = K × ε₀ × A / d, a high-K dielectric with a thin, reliably formed layer — like the sub-micron oxide in an electrolytic — is what makes a 10 000 µF can possible at all. The dielectric also fixes the voltage ceiling and, more often than not, the failure mode.
By polarity: polarized vs non-polarized
Polarized parts — aluminum electrolytics, tantalums and supercapacitors — get their oxide dielectric from an electrochemical forming step that only survives with the anode positive. Reverse them and the oxide dissolves or gas builds, with consequences from silent leakage to a vented can or a burning pellet. Non-polarized parts — ceramics, films, micas — work identically either way, which is mandatory for AC duty: audio coupling, motor run, crossover networks and snubbers. On the part, polarization is a stripe, a shorter lead or a marked terminal. Treating that marking as decoration is the single most expensive mistake in capacitor selection.
By construction: SMD vs through-hole
The same chemistry ships in packages with very different parasitics. Surface-mount MLCCs — multilayer ceramic chips from 0201 to 2220 — are by part count the most manufactured component on Earth, placed by the billion on pick-and-place lines; SMD tantalum and aluminum-polymer chips complete the surface-mount picture. Through-hole survives where current, voltage, cooling or serviceability demand it: snap-in and screw-terminal electrolytics in power supplies, radial film cans on motors, dipped micas in RF gear. Construction changes the numbers that matter at frequency — a leaded disc carries more stray inductance than an 0402 — so the “same” 10 µF can behave differently in two packages.
By application
The most practical axis, and the one this guide ends with: decoupling, coupling, timing, filtering, bulk smoothing, energy storage, motor run, audio crossover, pulse and snubber, RF resonance. Each application constrains the family list hard. A motor run capacitor must be a self-healing metallized polypropylene part rated for continuous AC voltage; a crystal load capacitor is a picofarad-scale C0G or a trimmer; a flash-lamp energy store is an electrolytic or a film pulse cap, never a Class 2 ceramic. The decision path near the end of this page turns these pairings into an ordered list.
Family Deep Dives
The Capacitor Families in Detail
Five deep dives and one round-up of the smaller families. Each covers structure, typical catalogue ranges, pros and cons, the characteristic failure mode, and the jobs the family wins. The ranges are the spreads you will meet across mainstream manufacturer catalogs — the specific part’s datasheet always has the final word.
Ceramic Capacitors — C0G, X7R and the MLCC Empire
A ceramic capacitor is layers of ceramic dielectric interleaved with printed metal electrodes, fired into one monolithic block — the multilayer ceramic capacitor, MLCC — or, in the older through-hole disc style, a single ceramic disc coated on both faces. There is no liquid, no electrolyte and no polarity: the dielectric is the ceramic itself. What varies between classes is that ceramic. Class 1 parts use paraelectric formulations chosen for stability; Class 2 and Class 3 use barium-titanate ferroelectrics chosen because their K reaches into the thousands, which is how a two-millimetre chip stores ten microfarads.
Capacitance
1 pF → ≈100 µF (largest MLCC sizes)
Voltage
6.3 V → several kV (discs, special MLCCs)
Tolerance
±1% C0G vs ±5–20% Class 2
Tempco
±30 ppm/°C C0G; ±15% X7R
Class 1 C0G (also sold as NP0) is the precision grade: capacitance drifts about ±30 ppm per degree Celsius — effectively zero — it does not age, shows no measurable loss under DC bias, and has very low loss, which is why RF tanks, crystal load circuits, precision timers and filters specify it. Class 2 X7R and X5R are the volume grade: cheap, tiny, available to tens of µF, but their capacitance falls with applied DC voltage (easily 20–80% at rated voltage, covered in the next section), ages a few percent per decade-hour, and exhibits a piezoelectric — microphonic — effect: the ceramic converts vibration into voltage noise and converts ripple current into audible singing. Class 3 Y5V trades everything for size, with swings up to +22%/−82% over its temperature range, and is best treated as obsolete for anything where the value matters.
Pros: lowest cost per part, smallest size, non-polarized, excellent high-frequency behavior, and effectively immortal at benign voltages. Cons: the bias-dependent value, loose Class 2 tolerance, microphonics, and the fact that sizes above roughly 10 µF print values instead of codes. The characteristic failure is a flex crack — board bending or hot-bar soldering cracks the ceramic body, and the crack can quietly short the internal layers; there is no vent and rarely a dramatic end, which makes the silent short the failure to design against. Applications: decoupling every IC supply pin (the classic 100 nF plus 10 µF pairing), crystal loading, RF resonant circuits, C0G timing, snubbers, and the multi-kilovolt discs that still hang across mains inputs in power electronics.
Aluminum Electrolytic Capacitors — the Bulk Workhorse
An aluminum electrolytic gets its capacitance from geometry no other family can match: the anode foil is electrochemically etched to multiply its surface area tens of times, then anodized so a sub-micron aluminum-oxide layer forms as the dielectric. A second foil — the cathode — connects through a liquid or gelled electrolyte that saturates a paper separator, and the sandwich is wound into an aluminum can. Because the oxide only survives with the anode positive, the part is firmly polarized.
Capacitance
1 µF → 100 000 µF
Voltage
6.3 V → 630 V standard
Tolerance
±20% typical
Load life
2 000–10 000 h at rated temp
Pros: the cheapest microfarad on the market by a wide margin, an unmatched range from 1 µF to beyond 10 000 µF, and big cans that swallow serious ripple current. Cons: polarity must be respected; tolerance is loose; the electrolyte turns to high resistance well below room temperature; and the part is a wear-out component — the electrolyte evaporates through the seal, so capacitance falls and ESR rises with every hot hour. That is the signature failure: dry-out drives ESR up, higher ESR dissipates more heat in ripple service, the heat accelerates dry-out, and the cycle ends at the scored vent — the characteristic bulged top or opened vent slot of a dead electrolytic. Reverse polarity or sustained overvoltage skips the slow path and produces gas fast enough to burst the can.
Applications follow from the strengths: bulk smoothing after rectifiers, DC-bus energy storage in inverters and drives, audio power-supply reservoirs, flash charging, and intermittent start-assist duty. When a design pairs them with ceramics — electrolytics for the bulk, ceramics for the fast currents — each family covers the other’s weakness, and that pairing is the default architecture of almost every power rail in existence.
Film Capacitors — Self-Healing Precision
Film capacitors use a plastic film — polyester (PET, the MKT family) and polypropylene (PP, the MKP family) dominate; PPS and PTFE serve specialty niches — as the dielectric itself, either metallized with a vapor-deposited aluminum layer or paired with separate foil electrodes, then wound or stacked into an epoxy-boxed part. The dielectric is micrometres thick, not nanometres like a formed oxide, which is exactly why film parts are physically large for their capacitance.
Capacitance
100 pF → ≈100 µF
Voltage
50 V → 2 kV (pulse: tens of kV)
Tolerance
±1–10% (±5% common)
ESR & loss
Very low, PP best-in-class
The headline property is self-healing: in a metallized film, a pinhole weakness in the dielectric vaporizes the ultra-thin metallization around the fault and cleanly isolates it — the capacitor survives its own breakdowns. That, plus no polarity, tight temperature behavior (polypropylene is especially stable and low-loss), low dielectric absorption and very low ESR, makes film the precision and power family. Cons: sheer size — a 10 µF film box dwarfs a 10 µF electrolytic — and cost at the high end. Failure is usually gradual: accumulated self-healing events slowly erode capacitance and insulation resistance over years, rather than ending in a short.
Applications: audio crossover networks and hi-fi signal coupling, motor run capacitors (metallized polypropylene is the universal choice, typically oil-impregnated in aluminum cans for HVAC compressors), X and Y safety capacitors across mains, snubbers and pulse-forming networks, and precision integrators and sample-hold stages where leakage and dielectric absorption would ruin the measurement.
Tantalum Capacitors — Maximum Microfarads, Strict Rules
A tantalum capacitor starts as a porous pellet sintered from tantalum powder — its internal surface is enormous — with a tantalum-pentoxide dielectric grown anodically over every pore wall. The cathode side is a solid manganese-dioxide (MnO₂) semiconductor layer in the classic style, or a conductive polymer in the newer premium style; the pellet is encased in epoxy SMD bodies or hermetic through-hole cans. The oxide formation makes it polarized, like the aluminum electrolytic, but with nothing liquid inside.
Capacitance
0.1 µF → ≈1 000 µF
Voltage
2.5 V → 50 V (most ≤ 35 V)
Tolerance
±10–20%
Temperature
−55…+125 °C grades
Pros: the best capacitance per volume of any polarized family, no dry-out because there is no liquid, stable behavior across temperature, and a long shelf life. Cons: expensive per microfarad compared with aluminum, voltage-limited, and unforgiving about both polarity and overvoltage. The characteristic failure mode is the reason for the family’s reputation: if the dielectric breaks down, the MnO₂ cathode supplies oxygen to the fault and the part can ignite — a genuine flame. Hence the universal derating practice: apply no more than 50% of rated voltage to MnO₂ tantalums (a 10 V part on a 5 V rail; a 6.3 V part on 3.3 V), and around 80% for polymer types, whose failure is gentler and usually just a short.
Applications: compact bulk capacitance beside processors in portable and embedded boards, output filtering where MLCC bias loss is unacceptable, decoupling of tightly regulated low-voltage rails, and high-reliability hermetic parts in aerospace, medical and downhole equipment where the solid construction outlives any wet electrolytic.
Supercapacitors (EDLC) — Farads, Not Microfarads
A supercapacitor — an electric double-layer capacitor, EDLC — has no conventional dielectric at all. Two activated-carbon electrodes, with on the order of a thousand square metres of surface per gram between them, face each other through a few nanometres of electrolyte, and charge physically accumulates in the double layer at each carbon-electrolyte interface. No dielectric is stressed or formed, which is why the parts survive hundreds of thousands of charge cycles and why capacitance reaches into thousands of farads.
Capacitance
1 F → ≈3 000 F per cell
Voltage
2.5–2.7 V per cell
Cycle life
≈500 000 cycles
Float life
10–20 years, leakage-limited
Pros: energy buffering with battery-like capacity and capacitor-like speed — seconds to charge, near-unlimited cycling, wide temperature operation. Cons: only 2.5–2.7 V per cell means any practical bank is a series string with resistive or active balancing; leakage current runs at milliamps, far above a battery’s self-discharge, so they are poor long-term storage; energy density is a small fraction of lithium chemistry; and voltage falls linearly with charge, so downstream electronics usually need a DC/DC converter. The characteristic failure is quiet: leakage and ESR grow with heat and age, and cells vent their electrolyte when pushed past their voltage rating.
Applications: RTC and memory backup, where a small cell holds a meter’s clock for days without a battery; bridging battery swaps in meters, trackers and handhelds; regenerative braking buffers in vehicles and elevators; wind-turbine pitch backup; and peak-load assist in grid-tied equipment where a battery would cycle itself to death. Wherever the job is many shallow cycles rather than long-term storage, the supercapacitor wins.
The Small Families: Mica, Paper, Oil-Filled and Trimmer
Four other families complete the map. Silvered-mica capacitors are the RF precision standard: roughly 1 pF to 100 nF, ±1% tolerance, superb Q and long-term stability, at a price that has pushed them into crystal oscillators, tuned filters and vintage-audio restoration, where nothing else quite substitutes. Paper capacitors are history: oil- or wax-soaked paper dielectrics built the electronics of the 1940s–60s, and their leakage and drift are why every restoration guide says replace them on sight. Oil-filled and pulse capacitors are film parts taken to the extreme — impregnated, metal-canned polypropylene rated for continuous AC in motor run duty or for kilo-amp pulse discharges in lasers, flash lamps and utility switchgear. Trimmer (variable) capacitors — small ceramic or plastic dielectric parts adjusted by screw, from a fraction of a pF up to about 100 pF — still align RF stages and calibrate oscillators where a fixed part cannot be trimmed precisely enough. None of these four will lead a modern bill of materials, but knowing they exist stops a lot of misidentification at the bench.
Side by Side
The Big Comparison Table
The grid below compresses the deep dives into one view. Every figure is a typical catalogue range — the kind of spread you can cross-check in the catalogs of mainstream manufacturers such as Murata, TDK, KEMET and Nichicon — not a guarantee for any specific part. Your datasheet, especially its derating curves, always wins over a table like this one.
Family
Capacitance range
Voltage range
Tolerance
Temp stability
ESR
Polarized?
Typical lifespan
Best use
Ceramic — C0G / NP0 (Class 1)
0.5 pF – 100 nF
16 V – 3 kV
±1% (±0.25 pF grades)
±30 ppm/°C — near-flat
Very low
No
Decades
RF, timing, precision filters
Ceramic — X7R / X5R (Class 2)
100 pF – 100 µF
6.3 V – 2 kV
±5–20%
±15% over temp + DC-bias loss
Low
No
Decades (value ages, drifts)
Decoupling and bypass
Aluminum electrolytic
1 µF – 100 000 µF
6.3 – 630 V
±20% typical
Value falls when cold
Moderate, rises with age
Yes
2 000–10 000 h at rated temp
Bulk smoothing, energy storage
Film (PET / PP)
100 pF – 100 µF
50 V – 2 kV (pulse to tens of kV)
±1–10%
±1–5% — stable
Very low
No
Decades, self-healing
Audio, motor run, pulse, safety
Tantalum (MnO₂ / polymer)
0.1 µF – 1 000 µF
2.5 – 50 V
±10–20%
Stable, −55…+125 °C grades
Moderate (lower for polymer)
Yes
Decades when derated to 50%
Compact high-µF rails
Supercapacitor (EDLC)
1 F – 3 000 F
2.5 – 2.7 V per cell
±20%
Capacitance drops in cold
Low
Yes (weakly)
10–20 years, ≈500 000 cycles
Backup power, energy buffering
This deep dive into the types of capacitors pairs with the site’s tools: the capacitor calculator on the homepage decodes any marking and computes charge and energy, while the calculators hub pairs every family-specific job — motor run, smoothing, timing, crossovers, high-voltage strings — with the tool that sizes it.
The Head-to-Head
Ceramic vs Electrolytic — the Decision Everyone Googles
Search data says this is the choice most people actually face, and it is simpler than the forum wars suggest: it is a division of labor, not a contest. Below roughly 10 µF — and always for fast, local decoupling — the ceramic MLCC wins on size, ESR, lifetime and cost. Above roughly 10–100 µF, and wherever bulk energy is the point, the aluminum electrolytic wins on capacitance per dollar and per cubic centimetre. A typical power rail uses both: 10 µF plus 100 nF of ceramic right at the IC pin, and hundreds or thousands of µF of electrolytic where the power enters the board.
Voltage headroom works differently for the two families. Aluminum electrolytics age with heat and voltage stress, so conservative practice derates them to 70–80% of rating — a 16 V part on a 12 V rail, a 450 V part on a 350 V bus — because lifetime hours scale steeply with applied voltage and temperature. Ceramics are the opposite: their dielectric is robust and running an X7R near its rated voltage is electrically safe. The ceramic’s problem is not survival — it is the value you actually get.
That value trap deserves its own paragraph, because it ambushes even experienced designers: a Class 2 ceramic can lose 20–80% of its rated capacitance under DC bias. A “10 µF” 0805 X7R rated at 6.3 V, sitting on a 5 V rail, may deliver nearer 3 µF, and the loss is worst at rated voltage combined with elevated temperature. The datasheet’s capacitance-versus-DC-bias curve is the real specification — not the headline number. The fixes: choose a larger case, choose a higher rated voltage, parallel several parts, or switch to a family without the effect (C0G for small values, film or properly derated tantalum for larger ones). Electrolytics barely notice DC bias; film and C0G do not care at all.
Cost crossover: below about 1 µF the ceramic wins outright on every axis; from 1–10 µF MLCC prices have fallen to where they usually win too, provided the bias loss is accounted for; from 10–100 µF it is genuinely case-by-case — the electrolytic is pennies, but a tantalum or aluminum-polymer chip may be the only thing that fits the height budget; beyond 100 µF the electrolytic dominates until supercapacitor territory. Lifetime cost counts too: the electrolytic is the part most likely to need replacement during the product’s life, while an MLCC, properly applied, usually outlives the board it is soldered to.
🔬Check the bias curve, not the headline
Check the bias curve, not the headlinePhoto: Unsplash
Decision Path
A Selection Decision Path
Run down the list and stop at the first line that matches the job in front of you. Each stop names the family and the reason in one breath; the table below links each application to the calculator that sizes it.
1
Decoupling an IC supply pin or a fast rail → X7R/X5R MLCC: the classic 100 nF per pin plus 1–10 µF per region, chosen from the bias curve, not the headline value.
2
Precision timing, active filters, crystal load, RF resonance → C0G/NP0 ceramic or film: the only families whose value you can trust to the percent over temperature and time.
3
Bulk smoothing and hold-up after a rectifier or on a DC bus → aluminum electrolytic: sized by ripple current and lifetime hours, not by capacitance alone.
4
Hi-fi signal coupling and loudspeaker crossovers → film, polypropylene preferred: low loss, no bias drift, no microphonics — the signal-path family.
5
Compact high-µF where height or area is scarce → tantalum or aluminum-polymer, derated to no more than 50% of rated voltage for MnO₂ chemistries.
6
Backup power, RTC keep-alive, bridging a battery swap → supercapacitor, in a balanced series string above 2.7 V.
7
Motor and HVAC compressor run duty → metallized polypropylene film, AC-rated: the familiar 35 µF / 440 V dual-run can.
8
A DC bus above any single part’s voltage → a series string of film capacitors with balancing resistors — never a lone electrolytic.
Every family dies in its own characteristic way, and knowing the signature tells you what to look for when a circuit misbehaves — short, open, leakage, vent or ignition.
Ceramic — the silent short
Flex or thermal cracks bridge the internal layers. No vent, no smoke — just a rail that droops. Inspect soldering stress and board flex first.
Aluminum electrolytic — dry-out to vent
ESR climbs, heat compounds it, the top bulges or the vent opens. Reverse polarity fast-tracks the same ending.
Film — graceful aging
Self-healing events accumulate; capacitance and insulation resistance drift down over years rather than failing shut.
Tantalum — ignition
Breakdown plus an oxygen-supplying cathode can flame. The 50% voltage derating rule exists for exactly this reason.
Supercapacitor — leakage and venting
Leakage grows with heat and age; sustained overvoltage past the cell rating vents the electrolyte.
Mica and paper — vintage liabilities
Paper leaks DC and drifts with humidity; replace on sight during restorations. Mica rarely fails but leads corrode.
Measurement closes the loop. The how to test a capacitor guide walks through the multimeter and under-load methods that separate a healthy part from a marginal one, and because a charged capacitor — especially a large electrolytic or a supercap — stays dangerous long after power-off, read how to discharge a capacitor before opening any enclosure.
Types of Capacitors — FAQ
What are the main types of capacitors?▼
The five families that cover nearly every capacitor you will meet are ceramic, aluminum electrolytic, film, tantalum and supercapacitor. Ceramic MLCCs span about 1 pF to 100 µF, are non-polarized and dominate decoupling. Aluminum electrolytics run from roughly 1 µF to tens of thousands of µF at 6.3–630 V and own bulk smoothing, at the cost of polarity, ±20% tolerance and a 2 000–10 000 h load life at rated temperature. Film capacitors (polyester, polypropylene) trade size for stability, self-healing and low ESR from about 100 pF to 100 µF. Tantalums pack 0.1–1 000 µF into small polarized packages. Supercapacitors reach 1–3 000 F at 2.5–2.7 V per cell for backup energy. Smaller niches belong to mica (RF precision), paper (obsolete) and trimmers (adjustable).
Ceramic vs electrolytic — which one should I use?▼
Divide the job, don't pick a winner: below about 10 µF and for all fast decoupling, use ceramics — smaller, non-polarized, effectively immortal, with far lower ESR. Above roughly 10–100 µF, or wherever bulk energy storage is the point, use aluminum electrolytics — the cheapest microfarads available, despite polarity, loose tolerance and limited lifetime. One trap decides it more often than cost: a Class 2 ceramic (X7R/X5R) can lose 20–80% of its capacitance under DC bias, so a '10 µF' chip may really be 3 µF on your rail — check the bias curve or parallel parts. An electrolytic instead needs 70–80% voltage derating for a long life and must never see reversed polarity.
What is an MLCC or SMD capacitor?▼
MLCC stands for multilayer ceramic capacitor — the small rectangular chip that makes up the overwhelming majority of surface-mount (SMD) capacitors placed today, in case sizes from 0201 to 2220. Inside, dozens of thin ceramic dielectric layers alternate with printed metal electrodes and sinter into one solid block, which is how a two-millimetre part reaches microfarads. Most SMD capacitor types are MLCCs, with SMD tantalum and SMD aluminum-polymer chips covering the compact high-µF slots. Note the marking habit: above roughly 10 µF, MLCCs print the value directly instead of a 3-digit code.
What do the codes X7R and C0G mean?▼
They are EIA temperature-coefficient classes for ceramic dielectrics. C0G (marketed as NP0) is Class 1: drift of about ±30 ppm/°C — essentially flat — no aging, no DC-bias loss and tolerances down to ±1%, but values are limited to roughly the pF–100 nF range. X7R is Class 2: it holds ±15% from −55 °C to +125 °C and reaches tens of µF, but loses capacitance under DC bias and ages slightly; X5R is the same idea with an +85 °C ceiling. Class 3 Y5V is the cautionary tale — swings up to +22%/−82% — and is best avoided wherever the value matters.
Are tantalum capacitors polarized, and why do they fail so dramatically?▼
Yes — both MnO₂ solid-electrolyte and polymer tantalum capacitors are polarized, and reverse connection or overvoltage destroys them. The dramatic reputation comes from the failure mechanism: when the tantalum-pentoxide dielectric breaks down, the MnO₂ cathode releases oxygen at the fault, feeding thermal runaway that can end in visible ignition. That is why the standing derating rule is to apply no more than 50% of the rated voltage to MnO₂ tantalums (a 10 V part on a 5 V rail), and about 80% for polymer types. Inside their limits they are excellent: high capacitance per volume, no dry-out, ±10–20% tolerance and −55…+125 °C grades.
How long do electrolytic capacitors last?▼
Aluminum electrolytics are wear-out parts: their liquid electrolyte slowly evaporates through the seal, so datasheets specify load life — commonly 2 000 to 10 000 hours at rated temperature (85 °C or 105 °C) and rated voltage. The rule of thumb doubles that for every 10 °C cooler, so the same part loafing at 45 °C inside a well-ventilated supply can serve well over a decade. Dying looks like rising ESR and falling capacitance, often with a bulged top or an opened vent. If an old can reads fine on a bench meter but the circuit misbehaves under load, suspect exactly that — measure it hot, in circuit, the way the under-load method does.
What is a supercapacitor used for?▼
A supercapacitor (EDLC) stores energy in the electric double layer at activated-carbon surfaces, which is how it reaches 1–3 000 F where ordinary capacitors stop at microfarads — but at only 2.5–2.7 V per cell, so higher voltages need balanced series strings. Typical uses: RTC and memory backup, where a small cell holds a meter's clock for days; battery-swap bridging in trackers and handhelds; regenerative energy buffering in vehicles and elevators; and peak-load assist where a battery would cycle itself to death. They charge in seconds and survive around 500 000 cycles, but their milliamp-scale leakage makes them poor long-term storage, and their energy density is far below lithium cells — they complement batteries rather than replace them.
Sources & Notes
The parameter ranges in the deep dives and in the comparison table are typical catalogue ranges, not guarantees for any specific product: they summarize the spreads you find across mainstream manufacturer catalogs — Murata, TDK Electronics, KEMET and Nichicon — cross-checked at the family level. The datasheet of the part in your hand, especially its capacitance-versus-DC-bias curves, lifetime ratings and ripple-current figures, always overrides anything on this page.
To keep search results honest about the difference between this page and the homepage: the homepage carries a compact five-row quick table of the capacitor families at /#types for a thirty-second answer, while this guide is the deep version — classification axes, per-family structure and failure modes, the full comparison grid, the ceramic-vs-electrolytic verdict and the application-to-calculator decision path.
The page is maintained as a selection reference: it exists to move you from “which family” to “which value” without requiring a parts-catalog education. Everything recommended here is checkable — each application row links to the calculator that sizes it, and every family claim traces back to a catalogue range you can verify with the manufacturers listed above.
Maintained by the CapacitorCalculator.com editorial team · Last updated: November 2, 2026
You now know which family fits the job. Next, ground the choice in the physics — what capacitance actually measures and why the families differ — then run your numbers in the calculator, free and entirely in your browser.
