Aillen MPP polypropylene film capacitors have excellent electrical characteristics compared to other dielectrics.Aillen polypropylene films have very low dielectric losses, high insulation resistance, low dielectric absorption and very high dielectric strength. In addition, the film has excellent resistance to moisture and very good long-term stability. The material has a negative temperature coefficient. Polypropylene capacitors are typically used in high frequency AC and pulse applications. They are further used in switching power supplies, electronic ballasts and buffer applications, for frequency discrimination and filtering circuits, and for energy storage, sampling and retention applications.
In the case of metallised capacitors, a thin aluminium layer (approx. 0.03 µm) is vacuum-deposited onto the insulating film as a conductive electrode. In the case of a breakdown, the short-circuit current causes the thin metal coating around the point of failure to evaporate, creating an insulating area. The capacitor remains intact (self-healing). Due to their construction principle, metallised capacitors stand out due to their very favourable capacitance/volume ratio.
The PCM metallised capacitors from 5 mm to 52.5 mm are available in two dielectric versions. The capacitors with polyester dielectric (PET) are suitable for general applications such as coupling, decoupling and bypassing. By using ultra thin films and appropriate manufacturing experience, high capacitance values can already be achieved in very small boxes. Polypropylene capacitors (PP) are used in high frequency applications. This includes resonant circuits, power supplies, deflection circuits, oscillator circuits and audio equipment.
A 4-pin version in a larger box size is available on request. Types with termination plates can also be manufactured on request. The advantages of this construction method, in addition to improved mechanical stability of the components on the board, are excellent electrical contact reliability.
Aillen capacitors are produced in proven box technology using solvent-resistant, flame-retardant plastic cases in accordance with UL 94 V-0. They are environmentally compliant with the EU regulation RoHS 2011/65/EU.
Widely used in high frequency, DC, AC and pulse circuits
Electronic ballasts, Switch - mode power supplies
Suitable for the situation where applies high frequency and high current pulse
Metalized polypropylene film, non-inductive wound construction
Low loss at high frequency
Small inherent temperature rise
Flame retardant epoxy resin coating
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Polypropylene for PP capacitors is a form of so-called film capacitor.
These capacitors use a thin plastic film as the dielectric - in this case polypropylene.
The film is made very thin and to the required thickness using a complex stretching process.
The polypropylene film can then be metallised and in this way formed into plates across the dielectric. Alternatively, the film can be left untreated and separate leaves of the conductor placed between the layers of the film to form the electrodes.
Either way, multiple layers of film are required to provide the required capacitance and the polar plates are connected to external leads.
Finally, the assembly is mounted in a case that protects it from damage and other environmental factors.
Polypropylene capacitors are widely available from many sources and are ideal for many applications, but there are some limitations to be aware of. Some of the key points to note regarding polypropylene capacitors are summarised below.
Tolerances: These capacitors are typically used where high tolerances are required. Capacitors with a 1% tolerance are available.
Stability: The capacitance of polypropylene capacitors varies very little with time and applied voltage, making them ideal for applications where stable capacitance levels are required. The temperature coefficient is found to be low, negative and almost linear.
ESR: PP capacitors have a low ESR, equivalent series resistance and, for most types, low inductance levels.
Leaded components: PP capacitors are available as leaded components only. No surface mount versions are available and ceramic capacitors in various forms are the most widely used.
Capacitance range: Polypropylene capacitors are available in a wide range of values. Typically, they range in value from approximately 100pF to 10 nF or even more
Voltage range: PP capacitors are capable of withstanding high voltages. Even small capacitors with an operating voltage of 630V or even 1kV are often seen, and 100V versions are common.
Temperature: These capacitors can operate at temperatures up to 100°C and sometimes just above with proper derating - although the manufacturer's specifications must be consulted before designing a particular component.
PP capacitors can be used in many electronic applications. Although only available in leaded versions, they are still widely used.
They are found in many applications.
High power/high AC voltage circuit applications.
Circuits with high peak current levels.