10. Tantalum electrolytic capacitors
Tantalum electrolytic capacitors come in two forms:
Foil tantalum electrolytic capacitor. The inner coiled core is used to negate the liquid electrolyte and the medium is tantalum oxide. Models are CA30, CA31, CA35, CAK35 and other series.
Tantalum powder sintering type. The anode (positive electrode) is made by pressing tantalum powder with very fine particles and sintering. Encapsulation comes in many forms. Models are CA40, CA41, CA42, CA42H, CA49, CA70 (non-polar) and other series.
The advantages are low dielectric loss, good frequency characteristics, high temperature resistance, low leakage current. Disadvantage is high production cost, low pressure. Widely used in communication, aerospace, military and household appliances in a variety of low and medium frequency circuit and time constant setting circuit.
11. Mica trimming capacitor
The mica trimming capacitor is composed of a fixed plate and a moving plate. The fixed plate is a fixed metal plate whose surface is pasted with a layer of mica sheet as the medium. The moving plate is an elastic copper or aluminum plate. Mica trimmer capacitor can be divided into single trimmer and double trimmer.
The advantage is that the capacitance can be repeatedly adjusted. Used in transistor radio, electronic instruments, electronic equipment.
12. Ceramic trimming capacitor
Ceramic-mediated trimming capacitors use ceramic as the medium. A semicircle silver layer is plated on both the moving plate (porcelain) and the fixed plate (porcelain). The electric capacity can be changed by changing the relative position between the two silver plates by rotating the moving plate.
Small size, can be adjusted repeatedly, easy to use. Used in transistor radio, electronic instruments, electronic equipment.
13. Thin film trimming capacitor
Thin film trimming capacitor uses organic plastic film as medium, that is, the organic plastic film is added between the moving piece and the fixed piece (both moving and fixed pieces are semicircles of metal), the screw on the moving piece is adjusted, the moving piece rotates, the capacity can be changed. Thin film trimming capacitors are generally divided into double trimming and four trimming. Some sealed double or sealed four variable capacitors come with a film trimming capacitor, trimming capacitor installed on the top of the shell, use and adjustment is more convenient.
Small size, light weight, can be adjusted repeatedly, easy to use. Used in transistor radio, electronic instruments, electronic equipment.
14. Air variable capacitor
The electrode consists of two sets of metal plates. One group is fixed plate, the other group is moving plate, and air is used as the medium between moving plate and fixed plate. When the moving piece is rotated so that all of it is rotated into the fixed piece, its electric capacity is the largest; otherwise, when all of the moving piece is rotated out of the fixed piece, the electric capacity is the smallest. Air variable capacitors can be divided into single and double connections.
The advantages are convenient adjustment, stable performance, not easy to wear. The disadvantage is that it is large. Used in radio, electronic instrument, high frequency signal generator, communication electronic equipment.
15. Film variable capacitor
Thin film variable capacitor is a plastic film as the medium between its moving plate and fixed plate, the shell is transparent or translucent plastic encapsulation, so it is also called sealed single or sealed double or sealed four variable capacitor.
The advantages are small size and light weight. Disadvantages are noisy, easy to wear. Single connection is mainly used in simple radio or electronic equipment; Double connection in transistor radios and electronic instruments, electronic equipment; Quadrint is commonly used on AF/FM multiband radios.
16. polypropylene capacitor
CBB capacitors are made of metallized polypropylene film in series structure, which can withstand high voltage and high current impact, with low loss, excellent electrical performance, high reliability and self-healing performance.
The advantages are high dielectric constant, small volume, large capacity, good stability, can resist high voltage, large current impact, with small loss, excellent electrical performance, high reliability and self-healing performance. The disadvantage is that the temperature coefficient is large. Replace most polystyrene or mica capacitors for more demanding circuits.
17. Safety capacitance
The composition of safety capacitor is generally composed of medium, electrode, shell, package, pin five parts. The medium is generally composed of polypropylene film; The electrode is composed of metal vacuum evaporation layer. The shell is generally flame retardant PBT plastic shell (UL94V-0); The package is generally composed of flame retardant epoxy resin (UL94V-0); The pin is made of tinned copper clad steel wire.
Do not cause electric shock, do not endanger personal safety. X capacitor is a capacitor connected between two lines of power line (L-N), which is used to suppress differential mode interference. Generally, metal film capacitor is used. Y capacitors are the capacitors that are connected between the two lines of the power line and the ground (L-E, N-E) respectively. They generally come in pairs to suppress common-mode interference. They are used at the input end of the power supply, i.e. when the capacitor fails, they will not cause electric shock and will not endanger personal safety.