Electromagnetic pulse valves are used to block low-frequency AC currents in high-altitude areas at low frequencies; Pulse DC to pure DC circuit; It is commonly found in the middle of two coupling capacitors at the output end of a bridge rectifier circuit, consisting of a choke and a capacitor Π Type low-pass filter. In high-frequency circuits: it is a high-frequency choke that prevents high-frequency currents from flowing into the low-frequency end in older remanufactured recorders; Obtain application.
Same as the above basic theories; It also blocks the pulse DC current after the rectifier from flowing into the choke of the pure DC router (to simplify the power circuit and control costs, pure resistors are used instead of the choke). Two capacitors (electrolytic capacitors) form a Pai low-pass filter. By utilizing the discharge efficiency of capacitors and the choking coil to direct current, the characteristic of blocking AC current is used to achieve smooth direct current and obtain authentic direct current.
People say that rectifiers convert alternating current into direct current, so fluctuations are the reverse process of converting direct current into alternating current. Everyone refers to the power circuit used in this process as an oscillator. The waveform of the oscillator includes sine wave, sawtooth wave, sawtooth wave, waveform, square wave, and peak wave. The frequency ranges from a few Hz to several tens of GHz. It is widely used in the wired and wireless industries.
In a control circuit, when current passes through an electrical conductor, it creates a magnetic field, and the size of the electromagnetic field is divided by the size of the current, which is called inductance. The definition of inductance is L=phi/i, and the enterprise is Weber.
Inductance is a parameter that considers the magnetic effect function of a special electromagnetic valve coil on current. Injecting current into a coil will create an electromagnetic field around the coil, and the coil will have magnetic flux based on it. The larger the switching power supply that enters the coil, the stronger the electromagnetic field, and the greater the magnetic flux of the coil. The experiment has confirmed that the ratio between the magnetic flux of the coil and the incoming current is proportional, and their ratio is called self inductance, also known as inductance. If based on the magnetic flux of the coil φ Indicating that current is represented by I and inductance is represented by L, then
L= φ／ I
The department of inductance is Heng (H), and it is also common to use milliHeng (mH) or micro Heng (uH) in enterprises. 1H=1000mH, 1H=1000000uH.
Inductance only works on unstable current, and its characteristic is that the two DC voltages are directly proportional to the instantaneous rate of change (derivative) of its current, and the proportional coefficient is its electromagnetic induction.
The factor that inductance plays is the electromagnetic field that changes when it passes through an unstable current, and this electromagnetic field can harm the current in the opposite direction. Therefore, all electrical conductors only need to rely on the electromagnetic field that changes according to the unstable current to harm the current in the opposite direction. Therefore, all conductive media will have self inductance phenomenon.
On the computer motherboard, you can see many coils of 4V explosion-proof solenoid valves wound with copper core wires, which are called inductors. Inductors are mainly divided into magnetic core inductors and hollow inductors. Large magnetic core inductors are commonly used in low-pass filters, while hollow inductors have smaller inductance and are commonly used in high-frequency circuits.
The characteristics of an inductor are exactly the opposite of those of a capacitor, which has the characteristic of blocking AC current and allowing DC current to pass through. The characteristics of an inductor are direct current and resistance for communication and exchange. The higher the frequency, the greater the characteristic impedance of the coil. Inductors often work together with capacitors in control circuits, forming LC filters, LC oscillators, etc. In addition, people also use the characteristics of inductance to produce and manufacture resistors, transformers, automotive relays, and so on.