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What is the status of the film capacitor industry chain?

  China is the largest producer of thin film capacitors, accounting for more than 60% of the global total output value. In 2020, the market size of China's film capacitance industry was 10.2 billion yuan.   With the application growth of thin film capacitors in new energy automobiles and photovoltaic fields, it is expected to produce more than 20 billion yuan incremental market scale in the next three years, and China's thin film capacitor market is expected to enter a high-speed growth period.   Thin film capacitor is a capacitor which takes electrical grade electronic thin film as dielectric and metal foil as electrodes and coils the electrodes with plastic thin film.   According to the current type, it can be divided into two types: DC film capacitance and AC film capacitance.   DC film capacitor is characterized by large capacity, low voltage resistance, polarity, self-healing characteristics, high reliability, good temperature stability and long service life. Typical applications include drivers, UPS, solar inverters, electronic ballasts, small motors for automobiles, household appliances, and various power sources.   AC film capacitor has the characteristics of small capacitance and high voltage resistance. It is an indispensable component in the application of conventional industrial AC power supply and the start and operation of asynchronous motor.   AC capacitors are widely used in AC output filters, especially output filters such as uninterruptible power supply (UPS) and photovoltaic inverters.   The function of thin film capacitor in photovoltaic inverters is mainly to absorb high pulse current at DC-Link end, make the voltage fluctuation at the inverter end stable and controllable, and play an important role in the stability and performance of photovoltaic devices.

What are the product categories of LED drivers?

  Led's drive is generally referred to as the Led's Luminous Module Controller, which controls the current. If the control current is not good, the lamp may be damaged. Sometimes the current and voltage can be very unstable, then the driver will play a role. So LED drives are very good to check for damage during use. If it is damaged, it can cause the light to dim or turn off directly, and it can also cause flashes.   Led driver is an electronic device that drives the LED light to emit light and work normally. It is equivalent to the heart of the LED lamp. When the driver is in problem, the whole LED lamp will be in problem.   Drivers can be categorized   (1) Constant current:   The output current of the constant current drive circuit is constant, but the output DC voltage varies in a certain range with the magnitude of the load resistance value. Load resistance value is small, output voltage is low, and the larger the load resistance value, the higher the output voltage is.   Constant current circuits are not afraid of short-circuit loading, but full open loading is strictly prohibited.   Constant current drive circuit for LED is ideal, but relatively expensive.   Pay attention to the maximum withstanding current and voltage value used, which limits the number of LEDs used.   (2) Voltage regulator:   When the various parameters of the voltage regulator circuit are determined, the output voltage is fixed, but the output current changes with the increase and decrease of the load.   The voltage regulator circuit is not afraid of load opening, but it is strictly forbidden to completely short-circuit the load.   Drive the LED with a regulator-driven circuit, each string needs to be added with a suitable resistor to make each LED display brightness average;   The brightness will be affected by the voltage change coming from the rectifier.

What is the parasitic effect of the capacitor

  A capacitor is an element that stores electric quantity and electric energy (electric potential energy). One conductor is surrounded by another conductor, or the electric field lines emitted by one conductor are all terminated in the conductor system of the other conductor, which is called a capacitor, including paper capacitors, mica capacitors, air capacitors, tantalum capacitors, thin film capacitors (polyethylene film, polystyrene film, polypropylene film, etc.), aluminum capacitors and ceramic capacitors.   Capacitors play an important role in tuning, bypass, coupling, filtering and other circuits. It is used in the tuning circuit of transistor radio and the coupling circuit and bypass circuit of color TV.   With the rapid development of electronic information technology, the updating speed of digital electronic products is getting faster and faster. The production and sales of consumer electronic products mainly including flat-panel TVs (LCD and PDP), notebook computers, digital cameras and other products continue to grow, driving the growth of the capacitor industry.   Parasitic means that the capacitance is not designed in that place, but there is always mutual capacitance between the wires, which is like parasitic capacitance between the wires, so it is called parasitic capacitance, also known as stray capacitance.   Parasitic capacitance generally refers to the capacitance characteristics of inductors, resistors, chip pins, etc. under high frequency conditions. In fact, a resistor is equivalent to a capacitor, an inductor, and a series connection of a resistor. It is not obvious at low frequency, but the equivalent value will increase at high frequency, which cannot be ignored. We should take it into account in the calculation. ESL is the equivalent inductance and ESR is the equivalent resistance. Whether it is resistance, capacitance, inductance, diode, triode, MOS transistor, or IC, we should consider their equivalent capacitance and inductance in the case of high frequency.   On the other hand, in addition to the capacitance between the plates, the sensor also has capacitive contact with the surrounding body (various elements and even the human body). This capacitance is called parasitic capacitance. It not only changes the capacitance of the capacitive sensor, but also the parasitic capacitance is extremely unstable due to the small capacitance of the sensor itself, which also leads to the unstable characteristics of the sensor and serious interference to the sensor.   Distributed capacitances distributed between wires, between coils and casings, and between some elements are called parasitic capacitances. Although their values are small, they are an important cause of interference.

What is the basic working principle of transformer?

  A transformer is a static electromagnetic device that converts electrical energy from one value to another. Basically, the transformer consists of an iron core and two coils called primary and secondary windings.   Transformer is a device that transforms AC voltage, current and impedance. When AC current is connected in the primary coil, AC magnetic flux will be generated in the iron core (or magnetic core), causing voltage (or current) to be induced in the secondary coil. The transformer is composed of an iron core (or magnetic core) and a coil. The coil has two or more windings, of which the winding connected to the power supply is called the primary coil, and the other windings are called the secondary coil.   The changing current in one coil of the transformer produces a changing magnetic flux, and then induces a changing electromotive force on the second coil wound on the same iron core. Electric energy can be transmitted between two coils, and there is no metal connection between the two circuits. The transformer can increase or decrease voltage and current levels without changing the frequency.   However, the winding process of transformer will have different requirements according to different applications (different purposes). The main functions of the transformer are: voltage transformation; Impedance transformation; Isolation; Voltage stabilization (magnetic saturation transformer), etc. the commonly used iron core shapes of transformers generally include E-type and C-type iron cores.   Transformers can be divided into: distribution transformer, power transformer, fully sealed transformer, combined transformer, dry-type transformer, single-phase transformer, electric furnace transformer, rectifier transformer, reactor, transformer, anti transformer, lightning transformer, box transformer, box transformer.   The most basic type of transformer consists of two groups of coils wound with wires, which are inductively combined with each other. When an AC current (with a certain known frequency) flows through one group of coils, an AC voltage with the same frequency will be induced in the other group of coils, and the magnitude of the induced voltage depends on the coupling of the two coils and the degree of magnetic cross-linking.