1. self-perception phenomenon
Self-induction phenomenon: The phenomenon of electromagnetic induction caused by the current change of the coil itself. The electromotive force generated in the self-inductance phenomenon is called self-inductance electromotive force; the current generated is called self-inductance current.
2. self-inductance coefficient and inductance
Self-inductance coefficient: the ratio of the self-inductance flux of the coil to the current I, also called self-inductance, referred to as inductance, expressed by the letter l, the unit of inductance is Henry, expressed by the symbol h.
3. common inductors
1. Outline of inductor:
Inductance coils can be divided into two categories: hollow and core inductance coils.
2. Inductor parameters
Inductors have two important parameters, one is inductance and the other is rated current.
● Inductance
Inductance is generally marked on the shell of the inductor, usually using the direct standard method or color code method, the unit is micro henry (uH).
● Rated current
The rated current refers to the large current allowed by the inductor during normal operation. It is often represented by letters A, B, C, D, and E. The nominal current is 50, 150, 300, 700, and 1600 mA respectively. In use, the actual working current of the inductor must be less than the rated current, otherwise the inductor coil will be severely heated or even burned.
Detection of 4. inductors
Measure the DC resistance at both ends of the inductor coil with the electric blocking "R × 1" block of the multimeter. Generally, the DC internal resistance of high-frequency inductors is between a few tenths and a few ohms; the internal resistance of low-frequency inductors is between a few hundred ohms and a few thousand ohms; the internal resistance of medium-frequency inductors is between a few ohms and tens of ohms.
The measured value is compared with the value specified in its technical standard: if the resistance value is much smaller than the specified resistance value, it means that the coil has a local short circuit or a serious short circuit; if the resistance value is large or the meter does not move, it means that the coil has an open circuit.