The inductor coil is formed on the insulating tube by a wire in a circle, and the wires are insulated from each other, and the insulating tube can be hollow or the core or magnetic core, referred to as an inductor. Tenked L, unit has Henry (H), millh, micro-Chinese (UH), 1H = 10 ^ 3MH = 10 ^ 6uh.
I. Classification of inductance
Press inductance: fixed inductance, variable inductance.
Classification of magnets: empty core coil, ferrite coil, iron core coil, copper core coil.
Classified by working nature: antenna coil, oscillating coil, choke coil, a trap coil, a deflection coil.
Press the winding structure classification: single layer coil, multi-layer coil, hive coil.
Second, the main characteristic parameters of the inductor coil
1, inductance amount L
The inductance amount L represents the inherent characteristics of the coil itself, independent of the current size. Except for specialized inductance coils (color code inductance), the amount of inductance is generally not specifically marked on the coil and is labeled in a specific name.
2, induction XL
The inductive coil is hindered by AC current, and the unit is ohm. It is related to the relationship between the inductance amount L and the AC frequency f, XL = 2πfl
3, quality factor Q
Quality factor Q is a physical quantity of the coil quality, Q is the ratio of the resistance XL and its equivalent resistance, namely: q = xl / r
The Q value of the coil is higher, the loss of the loop is less. The Q value of the coil is related to the DC resistance of the wire, the dielectric loss of the skeleton, the loss caused by the shield or core, and the impact of high-frequency skin effects. The Q value of the coil is usually tens to several hundred.
4, distributed capacitor
The coils of the coils and the turns, coils and shieldings, and the capacitance present between the coil and the bottom plate is referred to as a distributed capacitor. The presence of distributed capacitors reduces the Q value of the coil, and the stability is varied, so the smaller the distribution capacitance of the coil.
Third, common coil
1, single layer coil
Single-layer coils are on the paper tube or rubber frame with an insulated wire. Such as a transistor radio wave antenna coil.
2, hive-style coil
If the winding coil is not parallel to the rotating surface, but intersects a certain angle, such a coil is called a hive coil. And the number of times the wire is rotated back and forth, and it is often referred to as a depreciation. The advantage of the hive-style winding is that the size is small, the distributed capacitance is small, and the inductance is large. The hive coils are winding with hive windows, the more depreciation, the smaller distribution capacitance
3, ferrite magnetic core and iron core coil
The inductance size of the coil is related to the magnetic core. Insert the ferrite core in the hollow core coil, increase the inductance and improve the quality factors of the coil.
4, copper core coil
The copper core coil is used in the ultra-short wave range, and the inductance is changed by the position of the rotating copper core in the coil. This adjustment is relatively convenient and durable.
5, color code inductor
The color code inductor is an inductor having a fixed inductor, and its inductance marking method is the same as the resistance to mark.
6, blocking circle (choke)
The coil limiting the alternating current is called the damper ring, which is divided into high frequency resistance circle and low frequency blocking ring.
7, deflection coil
The deflection coil is the load of the television scan circuit output stage, the deflection coil requirements: the deflection sensitivity is high, the magnetic field is uniform, the Q value is high, the size is small, and the price is low.
transformer
The transformer is a device that transforms AC voltage, current, and impedance. When an AC current is communicated in the primary coil, an AC magnetic flux is generated, and a voltage (or current) is induced in the secondary coil. The transformer consists of a core (or magnetic core) and the coil, the coil has two or more windings, wherein the winding of the power supply is called a primary coil, and the remaining windings are called a secondary coil.
First, classification
Classified by cooling mode: dry (self-cooled) transformer, oil immersion (self-cooled) transformer, fluoride (evaporative cooling) transformer.
Classifying: Open transformers, potted transformers, sealed transformers.
Classification by iron core or coil: core transformer (instrument core, C-core, ferrite core), shell-type transformer (instrument core, C-core, ferrite core), Ring type transformer, metal foil transformer.
Press the power phase classification: single-phase transformer, three-phase transformer, multiphase transformer.
Classified by use: Power transformers, pressure regulating transformers, audio transformers, intermediate frequency transformers, high frequency transformers, pulse transformers.
Second, the characteristic parameters of the power transformer
1 operating frequency
The transformer core loss and frequency relationship is very large, so it should be designed and used according to the frequency of use, and this frequency is called the operating frequency.
2 rated power
At the specified frequency and voltage, the transformer can work for a long time without exceeding the output power of the specified temperature.
3 rated voltage
Refers to the voltage to be applied on the coil of the transformer, and must not be greater than the specified value.
4 voltage ratio
Refers to the ratio of the primary voltage and secondary voltage of the transformer, the difference between the no-load voltage ratio and the load voltage ratio.
5 no-load current
When the transformer is open, the primary still has a certain current, which is called a no-load current. The no-load current consists of magnetization current (generated magnetic flux) and iron loss current (caused by iron core loss). For a 50 Hz power transformer, the no-load current is substantially equal to the magnetization current.
6 No load: When the transformer is open, the power loss is measured in primary. The main loss is a core loss, followed by the loss (copper loss) generated by the no-load current in the copper resistance of the primary coil, which is small.
7 efficiency
The percentage of the ratio of the secondary power P2 and the primary power P1 ratio. Generally, the rated power of the transformer is higher, the higher the efficiency.
8 insulation resistance
Indicates the insulation performance between the coils of the transformer, each coil and the core. The height of the insulation resistance is related to the performance of the insulating material used, and the temperature is high and the humidity.
Third, audio transformers and high frequency transformer characteristics parameters
1 frequency response
Refers to the characteristics of the transformer secondary output voltage with the operating frequency.
2 passband
If the output voltage of the transformer is at U0, when the output voltage (input voltage remains unchanged), the frequency range of the transformer is referred to as a transformer, referred to as a transformer.
3 first, secondary impedance ratio
The primary and secondary access of the transformer, the appropriate impedance RO and Ri, enabling the transformer, secondary impedance, and the ratio of RO and RI is called the initial and secondary impedance ratio. In the case of impedance matching, the transformer works in optimum, and the transmission efficiency is the highest. Read more
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