Terminology interpretation of diode parameters

Terminology interpretation of diode parameters.

Pole capacitance of diode.

We know that diodes are easy to pass current from P-type to N-type semiconductors, but not easy to pass in the opposite direction. The combination of these two characteristics produces the function of a capacitor, that is, the role of accumulating electric charge. If you accumulate an electric charge, of course you have to discharge. Discharge can be carried out in any direction. Strictly speaking, it is not true that diodes have current flow in only one direction. This situation is obvious at high frequency. Therefore, the pole capacitance of the diode should be small.

Maximum rating.

Maximum reverse peak voltage VRM even if there is no reverse current, as long as the reverse voltage is continuously increased, the diode will be damaged sooner or later. The reverse voltage that can be added is not the instantaneous voltage, but the forward and backward voltage added repeatedly. Since AC voltage is applied to the rectifier, its maximum value is a specified important factor. Maximum DC reverse voltage VR the maximum reverse peak voltage mentioned above is the peak voltage added repeatedly, and VR is the value when the DC voltage is continuously added. For DC circuits, the maximum DC reverse voltage is important for determining the allowable and upper limit values.

Maximum surge current Isurge.

Excess forward current that is allowed to flow. It is not a normal current, but an instantaneous current, which is quite large.

Maximum average rectified current IO.

In a half-wave rectifier circuit, the maximum value of the average rectified current flowing through the load resistance. This is a very important value at design time.

Maximum AC input voltage VI.

The effective value of the sinusoidal AC voltage added to the half-wave rectifier circuit (resistance load). This is also a very important parameter when selecting a rectifier. Maximum peak forward current the maximum current value of IFM forward current, which is also an important parameter in the design of rectifier circuit.

Maximum power P.

If there is a current flowing through the diode, it will absorb heat and raise its own temperature. The maximum power P is the maximum value of power. Specifically, the voltage added to both ends of the diode is multiplied by the current flowing through it. This limit parameter is particularly important for voltage stabilizing diodes and variable resistance diodes.

Reverse current IR.

Generally speaking, there is no reverse current flow in the diode. In fact, when a certain reverse voltage is added, there will always be a current flow, which is called the reverse current. Needless to say, a good diode has a smaller reverse current.

Reverse recovery time.

When changing from a forward voltage to a reverse voltage, the ideal situation is that the current can be cut off instantly, in fact, it usually takes a little time to delay. The amount that determines the current cutoff delay is the reverse recovery time. Although it directly affects the switching speed of the diode, it does not necessarily mean that the value is small.