Temperature compensating capacitor

Use (As salts) Coloring and decolorizing glass, in temperature-compensating capacitors for radio, television, and radar. In carbon-arc cores (fluoride), in stainless steel (oxide), metallurgical research, textile treatment. 

Other uses of dysprosium are as a dopant in BaTiOa, which is used to make capacitors of small dimensions but with high capacity, and temperature compensating capacitors (Emsley 2001). 

Magnesium titanate has many useful applications, for example, in dew sensors, in pigments, and in the electrical and electronic industries as a dielectric material for manufacturing on-chip capacitors, high-frequency capacitors, and temperature compensating capacitors. 

Rutile bodies are used in either the pure form or with minor additions of various materials for capacitors (substitutes for mica, paper and electrolytics), temperature compensating (tc) capacitors, trimmer condensers, bypass condensers, filter and power circuits, and as fillers for resins and low melting glasses. 

A defined temperature coefficient of permittivity either close to zero (for capacitors with a capacity independent of temperature), or variable with negative or positive values (for the capacity compensation in circuits). 

Rare earth oxides are used for manufacturing ceramic capacitors. Their presence extends the capacitor s lifetime and improves some properties such as the compensation temperature coefficient, dielectricity and magnetic permeability. Specifically, Ce, La, Pr and Nd help keep the dielectric constant of a capacitor virtually unchanged [9]. 

Compensation for temperature-related frequency shifts can be accomplished by connecting a reactance (e.g., a variable voltage capacitor called a varactor) in series with the resonator. The effect of this reactance is to puU the frequency to cancel the effect of frequency drift caused by temperature changes. An example of a frequency vs. temperature characteristic both before and after compensation is shown in Fig. 3.8. Notice that the general form for the characteristic before compensation follows the cubic variation given earlier in this section. 

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