BFC238354333 vs MKT1820468635
| Part Number |
|
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| Category | Film Capacitors | Film Capacitors |
| Manufacturer | Vishay Beyschlag/Draloric/BC Components | Vishay Beyschlag/Draloric/BC Components |
| Description | CAP FILM 0.033UF 5% 1.6KVDC RAD | CAP FILM 0.68UF 10% 630VDC RAD |
| Package | Bulk | Bulk |
| Series | MMKP383 | MKT1820 |
| Features | - | - |
| Operating Temperature | -55°C ~ 105°C | -55°C ~ 125°C |
| Mounting Type | Through Hole | Through Hole |
| Package / Case | Radial | Radial |
| Applications | High Pulse, DV/DT | DC Link, DC Filtering |
| Tolerance | ±5% | ±10% |
| Size / Dimension | 1.024" L x 0.394" W (26.00mm x 10.00mm) | 1.240" L x 0.531" W (31.50mm x 13.50mm) |
| Termination | PC Pins | PC Pins |
| Voltage Rating - AC | 550V | 220V |
| Voltage Rating - DC | 1600V (1.6kV) | 630V |
| Lead Spacing | 0.886\" (22.50mm) | 1.083\" (27.50mm) |
| Ratings | - | - |
| Height - Seated (Max) | 0.768\" (19.50mm) | 0.925\" (23.50mm) |
| Capacitance | 0.033 µF | 0.68 µF |
| ESR (Equivalent Series Resistance) | - | - |
| Dielectric Material | Polypropylene (PP), Metallized | Polyester, Metallized |

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1. What is a paper film capacitor?
Paper film capacitors are actually a conceptual error because "paper film capacitors" are not a standard type of capacitor. Based on the information provided, you may want to ask about paper capacitors and film capacitors.
Paper capacitors
Paper capacitors are capacitors that use paper as a dielectric. It consists of thin paper as the dielectric and aluminum foil as the electrode, which is wound into a cylindrical shape and then impregnated with a shell or epoxy resin. Paper capacitors have the following characteristics:
Low cost: Paper capacitors are usually low-cost and suitable for mass production.
Large loss: Due to its material properties, paper capacitors have large losses.
Application scenarios: Mainly used for bypass, coupling, filtering, etc. in low-frequency circuits. -
2. Will the performance of film capacitors degrade?
Yes
The performance of film capacitors will degrade. The performance degradation of film capacitors is mainly due to their internal structure and material properties.
Reasons for performance degradation
Metal plating oxidation: During the capacitor manufacturing process, there is a trace amount of air between the film layers, which may be ionized under the action of the electric field to produce ozone. Ozone is a strong oxidant that oxidizes the metal plating to produce non-conductive metal oxides, resulting in a reduction in the plate area and a decrease in the capacitor capacity.
Humid air: During the winding process of film capacitors, if the workshop environment is not properly controlled, there will be a large amount of humid air. These humid air will produce air ionization reactions when the capacitor is working, generating ozone, which further causes the capacitor capacity to decay.
Poor quality materials: The film materials used are of poor quality, such as uneven evaporation and defects on the film, which will cause the capacitor capacity to decay.
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3. Can film capacitors be used for AC?
Yes
Film capacitors can be used for AC. Film capacitors can work normally in AC circuits and have specific application scenarios and advantages.
Structure and working principle of film capacitors
Film capacitors are mainly composed of metal foil (or foil obtained by metallizing plastic) as electrode plates and plastic film as dielectric. Common plastic films include polyethylene, polypropylene, polystyrene or polycarbonate. These capacitors are usually made by winding or stacking processes to form a cylindrical structure. -
4. What is the difference between foil capacitors and film capacitors?
Electrode materials, structure, and application areas
The main difference between foil capacitors and film capacitors lies in electrode materials, structures, and application areas.
Electrode materials and structures
Foil capacitors: Foil capacitors usually use metal foil as electrodes. This electrode is formed on a plastic film by vacuum evaporation, which is called a metallized film. This structure can save the thickness of the electrode foil, thereby reducing the volume of the capacitor and making it more miniaturized.
Film capacitors: Film capacitors use plastic films as dielectrics. Common plastic films include polyethylene, polypropylene, polystyrene or polycarbonate. These films overlap at both ends and are rolled into a cylinder to form a capacitor.

