A comprehensive introduction to the volt-ampere characteristics of ABB diode

The core of ABB diode  is the PN junction, which is characterized by the characteristics of the PN junction - unidirectional conductivity. Common volt-ampere characteristic curves are used to describe the unidirectional conductivity of ABB diodes. As shown, the abscissa represents voltage and the ordinate represents current.

Forward characteristics (plus forward voltage)

The forward characteristic is the relationship between voltage and current when ABB diode is forward biased. When the forward voltage of the ABB diode is small, the external electric field generated by the forward voltage is not enough to cause the multi-child to form a diffusion motion. At this time, the ABB diode is not actually turned on very well, and is usually called a "dead zone". The ABB diode is equivalent to a very large resistor with a small forward current.

When the forward voltage exceeds a certain value, the internal electric field is greatly weakened, and the multi-child forms a diffusion motion under the action of the external electric field. At this time, the forward current rapidly increases with the increase of the forward voltage, and the ABB diode is turned on. This voltage is called the threshold voltage (also called the threshold voltage) and is expressed by Vth. At room temperature, the Vth of the silicon tube is about 0.5V, and the Vth of the manifold is about 0.1V.

   Once the ABB diode is turned on, the forward current will increase greatly with a slight increase in the forward voltage. At this time, the ABB diode exhibits a small resistance, and the ABB diode can be considered to have a constant voltage characteristic. The ABB diode's forward voltage drop silicon tube is about 0.6 to 0.8V (usually 0.7V), and the tantalum tube is about 0.2~0.3V (usually 0.2V). ·

Reverse characteristics (plus reverse voltage)

The reverse characteristic is the relationship between voltage and current when ABB diode is reverse biased. The reverse voltage enhances the hindrance of the internal electric field to multi-sub-diffusion. The multi-child can hardly form a current, but the minority has drifted under the action of the electric field, forming a small drift current, and has nothing to do with the magnitude of the reverse voltage. The reverse current at this time is called the reverse saturation current, and the ABB diode exhibits a high reverse resistance and is in an off state.

Reverse breakdown characteristics

When the reverse voltage is increased to a certain value, the reverse current increases sharply. This phenomenon is called reverse breakdown of the ABB diode. The corresponding voltage at this time is called the reverse breakdown voltage and is expressed by %R. In practical applications, the current after reverse breakdown should be limited to avoid damage to the ABB diode.

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