What is a Polyester Capacitor?
Two metal plates are arranged between a polyester film and an insulator. If the polyester film is not suitable, a metalized film can be used as an alternative. There are capacitors made of polyester that have a capacitance between 1nF -15F, and they work between 50 and 1500 volts. Polyester capacitors are available in tolerance ranges of 5%, 10%, and 20%, and their temperature coefficients are high.
Since these capacitors have a high isolation resistance, they are excellent for storage and coupling. These capacitors are very much heat tolerant and frequently work at temperatures nearing about 150 degrees Celsius.
Polyester capacitors have very high capacitance per unit volume compared to other types; consequently, high-capacitance capacitors can be physically small. Polyester capacitors are cheap, making them widely used. Their usage ranges from audio circuits to oscillator circuits running at moderate frequency.
Construction
In most cases, aluminum or metallized foil is used as a partition between two metal plates. Capacitors store electric charge using dielectric film as an insulator between the plates. A cylindrical shape can be created by rolling and stacking the plates and films tightly together.
An outer protective coating is applied
to the capacitor to protect it from environmental factors. As a result of this coating, moisture and dust will not be able to damage internal components and the epoxy or polymer material will provide insulation.
Polyester Capacitor Types
Depending on their construction and intended use, polyester capacitors come in a variety of types. Here are a few examples:
Metallized:
One of the capacitor plates is formed by depositing thin metal film directly on polyester film. In applications where space is limited, this compact design is ideal.
Stacked Film:
Capacitors of this type are constructed by alternating layers of polyester film and metal foil. It is possible to handle higher voltages with stacked film capacitors due to their higher capacitance.
Box Type:
Plastic or epoxy boxes encapsulate box type capacitors with rectangular shapes. With high capacitance values, these capacitors are extra suitable for power supply circuits.
What is a Polypropylene Capacitor?
A polypropylene capacitor is constructed using a film of polypropylene as dielectric material. These devices are capable of storing and releasing electrical energy. In terms of electrical properties and reliability, polypropylene capacitors provide for excellent applications in circuits and devices for electronics.
Construction
In a polypropylene capacitor, the aluminum or metallized foil plate is sandwiched between two polypropylene films, separated by a very thin polypropylene film. The films serve as dielectrics between plate pairs and, thus, insulate the plates from each other. Cylindrical or rectangular shapes are formed by tightly rolling or stacking the plates and films.
A polymer or epoxy outer casing protects the capacitor from dust and moisture. Capacitor longevity is ensured by the casing, which provides insulation.
Comparison Between Polyester vs Polypropylene Capacitors
Stability
In the first polypropylene versus polyester comparison, we have the stability. The ability to maintain the capacitance value of capacitors depends on their stability because capacitors are constantly changing. Despite a wide temperature range, polyester capacitors maintain a stable capacitance. When consistency of performance is critical, polypropylene capacitors are even more reliable than metal capacitors.
Voltage Range
Voltage ranges indicate what voltage a capacitor can handle before it starts to fail. Several volts to several hundred volts are available in polyester capacitors. Whereas polypropylene capacitors would melt under high-voltage conditions, unlike theirs. Therefore, because of their relative ability to stand high voltage, they are preferred for high-voltage applications.
Tolerance
Inform us about the tolerance you are willing to accept from the stated capacitance value. Capacitors of polyester type may be available between 5% and 20%. The usual tolerance range of polypropylene capacitors is, however, between 1% and 5%. With further tolerance, polypropylene capacitors can be best suited for applications involving close tolerances.
High DV/DT
In polypropylene vs polyester comparison, Capacitors with dV/dt ratings are capable of handling rapid voltage changes without becoming overly stressed. The application of a polyester capacitor module is limited due to the transient ratings against its dV/dt thing–it says polypropylene capacitors better handle rapid changes of voltage because its dV/dt rating is quite high. This is one of the reasons why polypropylene capacitors are useful in quick switching applications.
Temperature
More specifically, applications subject to wide temperature swings tend to require capacitors with a broad operating temperature range. The temperature range of normal working conditions varies widely in polyester capacitors, that is -55°C to +125°C. Besides, in the case of polypropylene capacitors, it allows a range of -55°C to +105°C (with equivalent units -67°F to +221°F). A polypropylene capacitor is best suited for applications that expose it to significant temperature variation.
Final Verdict
On the whole, the differences in their utilization separate polyester and polypropylene capacitors from each other. The polyester capacitor is an all-around general-purpose device, while the polypropylene capacitor is suitably high frequency in an application. There is therefore no comparison; the polyester thus shows inferiority to the polypropylene capacitor in every aspect.
