BFC247965513 vs MMWA2P33K-F
| Part Number |
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| Category | Film Capacitors | Film Capacitors |
| Manufacturer | Vishay Beyschlag/Draloric/BC Components | Cornell Dubilier Electronics (CDE) |
| Description | CAP FILM 0.051UF 5% 630VDC RAD | CAP FILM 0.33UF 10% 250VDC AXIAL |
| Package | Tape & Reel (TR) | Bulk |
| Series | MKP479 | MMWA |
| Features | Long Life | - |
| Operating Temperature | -55°C ~ 105°C | -55°C ~ 125°C |
| Mounting Type | Through Hole | Through Hole |
| Package / Case | Radial | Axial |
| Applications | High Pulse, DV/DT | General Purpose |
| Tolerance | ±5% | ±10% |
| Size / Dimension | 0.728" L x 0.256" W (18.50mm x 6.50mm) | 0.366" Dia x 0.728" L (9.30mm x 18.50mm) |
| Termination | PC Pins | PC Pins |
| Voltage Rating - AC | 200V | 125V |
| Voltage Rating - DC | 630V | 250V |
| Lead Spacing | 0.591\" (15.00mm) | - |
| Ratings | - | - |
| Height - Seated (Max) | 0.630\" (16.00mm) | - |
| Capacitance | 0.051 µF | 0.33 µF |
| ESR (Equivalent Series Resistance) | - | - |
| Dielectric Material | Polypropylene (PP), Metallized | Polyester, Metallized |
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1. Is a film capacitor AC or DC?
AC, DC
Film capacitors can be used in both AC and DC circuits. According to the current type, film capacitors can be divided into DC film capacitors and AC film capacitors.
DC film capacitors
DC film capacitors are mainly used in DC circuits and have the following characteristics:
Large capacity: has a higher capacitance.
Low withstand voltage: the withstand voltage value is relatively low.
Polarity: has positive and negative poles.
Application scenarios: commonly used in motor drives, uninterruptible power supplies (UPS), solar inverters, electronic ballasts, small automotive motors, household appliances, etc.
AC film capacitors
AC film capacitors are mainly used in AC circuits and have the following characteristics:
Small capacity: relatively small capacitance.
High withstand voltage: high withstand voltage value.
Pass AC, block DC: conduct electricity in AC circuits, equivalent to open circuits in DC circuits.
Application scenarios: widely used in industrial AC power supplies, asynchronous motor starting and operation, uninterruptible power supplies (UPS) and output filters of photovoltaic inverters, etc. -
2. What are the uses of power film capacitors?
Power film capacitors are widely used in power systems, communication equipment, automotive electronics and household appliances.
Power system
In power systems, power film capacitors are mainly used in high-voltage direct current transmission (HVDC) and reactive power compensation devices. HVDC transmission has the advantages of long transmission distance, low loss and small impact on the environment. Power film capacitors can effectively improve the voltage stability of the system, reduce voltage fluctuations and improve the quality of electric energy. In addition, power film capacitors can also be used in reactive power compensation devices. By adjusting the reactive power in the power grid, the power factor of the power grid can be improved, line loss can be reduced and the utilization rate of electric energy can be improved.
Communication equipment
In communication equipment, power film capacitors are mainly used in devices such as filters, couplers and isolators. Filters are key components in communication equipment, which are used to eliminate noise and interference in signals. Power film capacitors are small in size, light in weight and have good frequency characteristics, which can effectively improve the performance of filters. Couplers and isolators are used for signal transmission and isolation. Power film capacitors can achieve high-frequency and high-isolation coupling and isolation functions to meet the high-performance requirements of communication equipment.
Automotive electronics
In the field of automotive electronics, power film capacitors are used in electronic control units (ECUs), motor controllers, and battery management systems. ECUs are the core components of automotive electronic systems and are responsible for controlling various functions of the car. Power film capacitors can improve their reliability and stability. Motor controllers are key components of electric vehicles and are responsible for controlling the speed and torque of the motor. Power film capacitors can achieve efficient and high-precision motor control functions. Battery management systems are responsible for monitoring and managing battery status. Power film capacitors can improve their accuracy and stability.
Household appliances
In the field of household appliances, power film capacitors are mainly used in home appliances such as air conditioners, refrigerators, and washing machines. These home appliances usually require high power and high-frequency applications. The high-frequency filtering and bypass characteristics of power film capacitors make them perform well in these applications. -
3. 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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4. How do film capacitors fail?
High working environment temperature, improper selection of working current, exceeding the specified working voltage, harmonic current
The main reasons for film capacitor failure include the following:
High working environment temperature: Film capacitors can work normally in a temperature environment of -40℃~+105℃, but exceeding this range will accelerate thermal aging, resulting in a shortened service life, and even bursting in severe cases.
Improper selection of working current: The current value in the circuit should be less than the current value allowed by the film capacitor, otherwise it will cause the capacitor to heat up, and long-term use will shorten the life, and even burst in severe cases.
Exceeding the specified working voltage: Excessive voltage will cause partial discharge, which will then break down the capacitor and cannot be used.
There are harmonic currents: high-order harmonic currents are superimposed on fundamental currents, resulting in an increase in total current, causing capacitor load overload, internal expansion, and explosion.
Buying inferior capacitors: In order to reduce costs, some manufacturers on the market use low-quality materials to produce capacitors, which greatly reduces the actual withstand voltage and life of such capacitors.
The structural characteristics of film capacitors and the impact of the use environment on their performance:
Film capacitors are usually composed of polypropylene film, aluminum foil and plastic shell. Polypropylene film is sensitive to high temperature, which accelerates its aging and shortens the life of the capacitor. In addition, a humid environment will also cause water vapor to enter the capacitor, affecting its performance.
