Comparison
| Capacitor type | Dielectric | Features/applications | Disadvantages |
|---|---|---|---|
| Ceramic capacitors | |||
| Ceramic Class 1 capacitors | paraelectric ceramic mixture of Titanium dioxide modified by additives | Predictable linear and low capacitance change with operating temperature. Excellent high frequency characteristics with low losses. For temperature compensation in resonant circuit application. Available in voltages up to 15,000 V | Low permittivity ceramic, capacitors with low volumetric efficiency, larger dimensions than Class 2 capacitors |
| Ceramic Class 2 capacitors | ferroelectric ceramic mixture of barium titanate and suitable additives | High permittivity, high volumetric efficiency, smaller dimensions than Class 1 capacitors. For buffer, by-pass and coupling applications. Available in voltages up to 50,000 V. | Lower stability and higher losses than Class 1. Capacitance changes with change in applied voltage, with frequency and with aging effects. Slightly microphonic |
| Film capacitors | |||
| Metallized film capacitors | PP, PET, PEN, PPS, (PTFE) | Metallized film capacitors are significantly smaller in size than film/foil versions and have self-healing properties. | Thin metallized electrodes limit the maximum current carrying capability respectively the maximum possible pulse voltage. |
| Film/foil film capacitors | PP, PET, PTFE | Film/foil film capacitors have the highest surge ratings/pulse voltage, respectively. Peak currents are higher than for metallized types. | No self-healing properties: internal short may be disabling. Larger dimensions than metallized alternative. |
| Polypropylene (PP) film capacitors | Polypropylene (Treofan®) |
Most popular film capacitor dielectric. Predictable linear and low capacitance change with operating temperature. Suitable for applications in Class-1 frequency-determining circuits and precision analog applications. Very narrow capacitances. Extremely low dissipation factor. Low moisture absorption, therefore suitable for "naked" designs with no coating. High insulation resistance. Usable in high power applications such as snubber or IGBT. Used also in AC power applications, such as in motors or power factor correction. Very low dielectric losses. High frequency and high power applications such as induction heating. Widely used for safety/EMI suppression, including connection to power supply mains. | Maximum operating temperature of 105 °C. Relatively low permittivity of 2.2. PP film capacitors tend to be larger than other film capacitors. More susceptible to damage from transient over-voltages or voltage reversals than oil-impregnated MKV-capacitors for pulsed power applications. |
| Polyester (PET) film (Mylar) capacitors |
Polyethylene terephthalate, Polyester (Hostaphan®, Mylar®) | Smaller in size than functionally comparable polypropylene film capacitors. Low moisture absorption. Have almost completely replaced metallized paper and polystyrene film for most DC applications. Mainly used for general purpose applications or semi-critical circuits with operating temperatures up to 125 °C. Operating voltages up to 60,000 V DC. | Usable at low (AC power) frequencies. Limited use in power electronics due to higher losses with increasing temperature and frequency. |
| Polyethylene naphthalate (PEN) film capacitors |
Polyethylene naphthalate (Kaladex®) | Better stability at high temperatures than PET. More suitable for high temperature applications and for SMD packaging. Mainly used for non-critical filtering, coupling and decoupling, because temperature dependencies are not significant. | Lower relative permittivity and lower dielectric strength imply larger dimensions for a given capacitance and rated voltage than PET. |
| Polyphenylene Sulfide (PPS) film capacitors |
Polyphenylene (Torelina®) | Small temperature dependence over the entire temperature range and a narrow frequency dependence in a wide frequency range. Dissipation factor is quite small and stable. Operating emperatures up to 270 °C. Suitable for SMD. Tolerate increased reflow soldering temperatures for lead-free soldering mandated by the RoHS 2002/95/European Union directive | Above 100 °C, the dissipation factor increases, increasing component temperature, but can operate without degradation. Cost is usually higher than PP. |
| Polytetrafluoroethylene (PTFE) (Teflon film) capacitors |
Polytetrafluoroethylene (Teflon®) | Lowest loss solid dielectric. Operating temperatures up to 250 °C. Extremely high insulation resistance. Good stability. Used in mission-critical applications. | Large size (due to low dielectric constant). Higher cost than other film capacitors. |
| Polycarbonate (PC) film capacitors |
Polycarbonate | Almost completely replaced by PP | Limited manufacturers |
| Polystyrene (PS) film capacitors |
Polystyrene (Styroflex) | Almost completely replaced by PET | Limited manufacturers |
| Polysulphone film capacitors | Polysulfone | Similar to polycarbonate. Withstand full voltage at comparatively higher temperatures. | Only development, no series found (2012) |
| Polyamide film capacitors | Polyamide | Operating temperatures of up to 200 °C. High insulation resistance. Good stability. Low dissipation factor. | Only development, no series found (2012) |
| Polyimide film (Kapton) capacitors |
Polyimide (Kapton) | Highest dielectric strength of any known plastic film dielectric. | Only development, no series found (2012) |
| Film-based power capacitors | |||
| Metallized paper power capacitors | Paper impregnated with insulating oil or epoxy resin | Self-healing properties. Originally impregnated with wax, oil or epoxy. Oil-Kraft paper version used in certain high voltage applications. Mostly replaced by PP. | Large size. Highly hygroscopic, absorbing moisture from the atmosphere despite plastic enclosures and impregnates. Moisture increases dielectric losses and decreases insulation resistance. |
| Paper film/foil power capacitors | Kraft paper impregnated with oil | Paper covered with metal foils as electrodes. Low cost. Intermittent duty, high discharge applications. | Physically large and heavy. Significantly lower energy density than PP dielectric. Not self-healing. Potential catastrophic failure due to high stored energy. |
| PP dielectric, field-free paper power capacitors (MKV power capacitors) |
Double-sided (field-free) metallized paper as electrode carrier. PP as dielectic, impregnated with insulating oil, epoxy resin or insulating gas | Self-healing. Very low losses. High insulation resistance. High inrush current strength. High thermal stability. Heavy duty applications such as commutating with high reactive power, high frequencies and a high peak current load and other AC applications. | Physically larger than PP power capacitors. |
| Single- or double-sided metallized PP power capacitors |
PP as dielectric, impregnated with insulating oil, epoxy resin or insulating gas | Highest capacitance per volume power capacitor. Self-healing. Broad range of applications such as general-purpose, AC capacitors, motor capacitors, smoothing or filtering, DC links, snubbing or clamping, damping AC, series resonant DC circuits, DC discharge, AC commutation, AC power factor correction. | critical for reliable high voltage operation and very high inrush current loads, limited heat resistance (105 °C) |
| PP film/foil power capacitors | Impregnated PP or insulating gas, insulating oil, epoxy resin or insulating gas | Highest inrush current strength | Larger than the PP metallized versions. Not self-healing. |
| Electrolytic capacitors | |||
| Electrolytic capacitors with non solid (wet, liquid) electrolyte |
Aluminum dioxide Al2O3 |
Very large capacitance to volume ratio. Capacitance values up to 2,700,000 µF/6.3 V. Voltage up to 550 V. Lowest cost per capacitance/voltage values. Used where low losses and high capacitance stability are not of major importance, especially for lower frequencies, such as by-pass, coupling, smoothing and buffer applications in power supplies and DC-links. | Polarized. Significant leakage. Relatively high ESR and ESL values, limiting high ripple current and high frequency applications. Lifetime calculation required because drying out phenomenon. Vent or burst when overloaded, overheated or connected wrong polarized. Water based electrolyte may vent at end-of-life, showing failures like "capacitor plague" |
| Tantalum pentoxide Ta2O5 |
Wet tantalum electrolytic capacitors (wet slug) Lowest leakage among electrolytics. Voltage up to 630 V (tantalum film) or 125 V (tantalum sinter body). Hermetically sealed. Stable and reliable. Military and space applications. | Polarized. Violent explosion when voltage, ripple current or slew rates are exceeded, or under reverse voltage. Expensive. | |
| [Electrolytic capacitors with solid ] electrolyte |
Aluminum dioxide Al2O3 Tantalum pentoxide Ta2O5, Niobium pentoxide Nb2O5 |
Tantalum and niobium with smaller dimensions for a given capacitance/voltage vs aluminum. Stable electrical parameters. Good long-term high temperature performance. Lower ESR lower than non-solid (wet) electrolytics. | Polarized. About 125 V. Low voltage and limited, transient, reverse or surge voltage tolerance. Possible combustion upon failure. ESR much higher than conductive polymer electrolytics. Manganese expected to be replaced by polymer. |
| Electrolytic capacitors with solid Polymer electrolyte (Polymer capacitors) |
Aluminum dioxide Al2O3, Tantalum pentoxide Ta2O5, Niobium pentoxide Nb2O5 |
Greatly reduced ESR compared with manganese or non-solid (wet) elelectrolytics. Higher ripple current ratings. Extended operational life. Stable electrical parameters. Self-healing. Used for smoothing and buffering in smaller power supplies especially in SMD. | Polarized. Highest leakage current among electrolytics. Higher prices than non-solid or manganese dioxide. Voltage limited to about 100 V. Explodes when voltage, current, or slew rates are exceeded or under reverse voltage. |
| Supercapacitors | |||
| Supercapacitors Pseudocapacitors |
Helmholtz double-layer plus faradaic pseudo-capacitance | Energy density typically tens to hundreds of times greater than conventional electrolytics. More comparable to batteries than to other capacitors. Large capacitance/volume ratio. Relatively low ESR. Thousands of farads. RAM memory backup. Temporary power during battery replacement. Rapidly absorbs/delivers much larger currents than batteries. Hundreds of thousands of charge/discharge cycles. Hybrid vehicles. Recuperation | Polarized. Low operating voltage per cell. (Stacked cells provide higher operating voltage.) Relatively high cost. |
| Hybrid capacitors Lithium ion capacitors (LIC) |
Helmholtz double-layer plus faradaic pseudo-capacitance. Anode doped with lithium ions. | Higher operating voltage. Higher energy density than common EDLCs, but smaller than lithium ion batteries (LIB). No thermal runaway reactions. | Polarized. Low operating voltage per cell. (Stacked cells provide higher operating voltage.) Relatively high cost. |
| Miscellaneous capacitors | |||
| Air gap capacitors | Air | Low dielectric loss. Used for resonating HF circuits for high power HF welding. | Physically large. Relatively low capacitance. |
| Vacuum capacitors | Vacuum | Extremely low losses. Used for high voltage, high power RF applications, such as transmitters and induction heating. Self-healing if arc-over current is limited. | Very high cost. Fragile. Large. Relatively low capacitance. |
| SF6-gas filled capacitors | SF6 gas | High precision. Extremely low losses. Very high stability. Up to 1600 kV rated voltage. Used as capacitance standard in measuring bridge circuits. | Very high cost |
| Metallized mica (Silver mica) capacitors | Mica | Very high stability. No aging. Low losses. Used for HF and low VHF RF circuits and as capacitance standard in measuring bridge circuits. Mostly replaced by Class 1 ceramic capacitors | Higher cost than class 1 ceramic capacitors |
| Glass capacitors | Glass | Better stability and frequency than silver mica. Ultra-reliable. Ultra-stable. Resistant to nuclear radiation. Operating temperature: −75 °C to +200 °C and even short overexposure to +250 °C. | Higher cost than class 1 ceramic |
| Integrated capacitors | oxide-nitride-oxide (ONO) | Thin (down to 100 µm). Smaller footprint than most MLCC. Low ESL. Very high stability up to 200 °C. High reliability | Customized production |
| Variable capacitors | |||
| Air gap tuning capacitors | Air | Circular or various logarithmic cuts of the rotor electrode for different capacitance curves. Split rotor or stator cut for symmetric adjustment. Ball bearing axis for noise reduced adjustment. For high professional devices. | Large dimensions. High cost. |
| Vacuum tuning capacitors | Vacuum | Extremely low losses. Used for high voltage, high power RF applications, such as transmitters and induction heating. Self-healing if arc-over current is limited. | Very high cost. Fragile. Large dimensions. |
| SF6 gas filled tuning capacitor | SF6 | Extremely low losses. Used for very high voltage high power RF applications. | Very high cost, fragile, large dimensions |
| Air gap trimmer capacitors | Air | Mostly replaced by semiconductive variable capacitance diodes | High cost |
| Ceramic trimmer capacitors | Class 1 ceramic | Linear and stable frequency behavior over wide temperature range | High cost |
Read more about this topic: Types Of Capacitor
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