Learn to test electronic components and inductors only need to master these points

Date：2021-04-29 16:07:00Views：1323

Inductance: when the coil passes through the current, a magnetic field induction is formed in the coil, and the induced magnetic field will generate induced current to resist the current passing through the coil. We call this interaction between current and coil electrical reactance, that is, inductance, and the unit is "Henry" (H). This property can also be used to make inductive elements. Inductance is usually represented by "L" plus number in the circuit. For example, L6 represents the inductance numbered 6. The inductive coil is made by winding the insulated conductor on the insulated skeleton for a certain number of turns. DC can pass through the coil. DC resistance is the resistance of the conductor itself, and the voltage drop is very small; When the AC signal passes through the coil, the self induced electromotive force will be generated at both ends of the coil. The direction of the self induced electromotive force is opposite to the direction of the applied voltage, which hinders the passage of AC. therefore, the characteristic of the inductance is DC resistance AC. the higher the frequency, the greater the coil impedance. Inductance and capacitance can form an oscillation circuit in the circuit. Inductance generally has direct mark method and color mark method, which is similar to resistance. For example, brown, black, gold and gold represent 1uh (error 5%) inductance. The basic unit of inductance is Heng (H), and the conversion units are 1H = 103mh = 106uh.

Identification of inductive devices

Inductive devices can be divided into two categories: one is the inductive coil using self induction; The second is the transformer with mutual inductance. Inductance coil is generally referred to as inductance. Inductance has a wide range of applications. It is essential in tuning, oscillation, coupling, matching, filtering, notch, delay, compensation and deflection circuits. In fact, inductance is a kind of coil, which can establish (or induce) voltage to reflect the change of current through the coil. In other words, with the change of the current flowing through the coil, a voltage in a certain direction will be induced inside the coil to reflect the change of the current passing through the coil. In the circuit, the symbol of inductance is（）The basic unit is share, and the letter symbol is h. The commonly used inductance values include millishare (MH) and micro share (Uh). The conversion relationship is 1H = 103mh = 106uh. Inductance is similar to resistance. It has no positive and negative poles. It can be connected arbitrarily in the circuit, but the coupled coils must be connected in a special way.

Function of inductor

The main function of inductance is to isolate traffic, which is also one of its characteristics. There is also the role of filtering and forming a resonant circuit.

Detection of inductors

The quality of the inductor can be detected with a multimeter. As shown in the figure, place the multimeter in "R" × 1 "gear, the two probes (regardless of positive and negative) are connected with the two pins of the inductor, the indication of the probe should be close to" 0 Ω ", and the inductor with large inductance should have a certain resistance value. If the needle does not move, it indicates that the inductor is internally open; If the indication of the gauge needle is unstable, it indicates poor internal contact.