PMR A

This natural mineral insulator has outstanding dielectric properties that are ideal for long-life high-stability capacitors with low loss at all frequencies, and high dielectric strength. This type of capacitor is used particularly for high frequency and delay line applications, oscillating circuits, emission devices and calibrators.

Mica dielectric capacitor technology allows for several custom design applications including: 

• High voltage capacitors (up to 50 kV)
• High temperature capacitors (up to 250°C)
• Precision capacitors (up to ± 0.1%)
• High stability capacitors (– 20 + 30 ppm/°C)
• High frequency capacitors ( up to several GHz). 

The majority of these capacitors are manufactured to comply to specifications NF-C-83120;MIL-C-5 and MIL-PRF-39001 standards.

Mica capacitors are noted for the following characteristics:

• Temperature performance
• Low loss at all frequencies
• High dielectric strength
• Stability over time

Silver mica capacitors provide superior stability and low loss when used in RF power circuits that require low pico farad (pF) and nano farad (nF) ranges. Older silver mica capacitors were manufactured in layers of mica and silver, but the layering allowed room for air gaps that reduced the stability and could also create stress fractures in the assembly.

Modern manufacturing uses silver plated to mica layers, eliminating the gaps. When the desired number of layers is obtained, the assembly is coated in an epoxy or ceramic resin. The coating reduces fracturing of the layers and seals the assembly from moisture and particles that could interfere with the capacitance value.

Mica capacitors are useful in circuits for ripple filtering and are often found in time constant, coupling or resonance circuits. In addition to radio circuits, they are used in TV transmitters and Cable TV amplification circuits. Mica is also a superior choice in high-voltage inversion and power conversion for energy absorbing snubber applications with capacitances of up to 10 nF.

Standard silver mica capacitors are normally designed to handle voltages from 100 to 1000 volts. High-voltage RF transmitter applications can call for higher tolerances. Mica capacitors are available for voltages up to 20kV.

Our expert engineering team can create the mica capacitor with the characteristics you require. Send us your drawing or file and we will work with you to manufacture the correct size, lead style and capacitance you desire.

Dielectric Tuning Elements are used whenever the lowest loss tuning for high frequency applications is required. When dielectric rod is introduced into a cavity, the self resonant frequency is lowered due to the cavity “appearing” larger. 

 The basic dielectrics used in Exxelia Ceramics Microwave Tuning Elements are sapphire, quartz and alumina. 

Film capacitors are used in a wide variety of different industry, including with military technology and applications as well as the aerospace industry. This is mainly due to the fact that they have high long term stability, can be produced relatively cheaply and are heat resistant. 

One of the main characteristics of our film capacitor comes from the fact that they are not polarized. Due to this design element, they are available for use in both AC power and signal applications. 

They are also designed to have high precision capacitance values, which means that they can retain their value for a much longer period of time than capacitors of other types. The aging process of these types of capacitors is generally much slower than it would be if a different type of material were being used during construction.

Aluminum electrolytic capacitors, also commonly known as just electrolytic capacitors, are a unique type of configuration that uses an electrolyte to achieve a capacitance that is much larger than other types of these devices. The electrolyte in question is usually either a gel or a liquid that itself contains a very high concentration of polarized ions. Polarization indicates that the voltage on the positive terminal is always larger than the similar voltage on the negative terminal of the capacitor.

One of the major benefits of these types of aluminum electrolytic capacitors is the aforementioned large capacitance. They do, however, have a number of disadvantages when compared to other types of capacitors. Aluminum electrolytic capacitors have a large leakage current when compared to capacitors of other types. Additional disadvantages include a limited lifetime, value tolerances and an equivalent resistance series.