The crystal diode is a p-n junction formed by a p-type semiconductor and an n-type semiconductor, and a space charge layer is formed on both sides of the interface, and a self-built electric field is built. When there is no applied voltage, the diffusion current caused by the difference in the carrier concentration on both sides of the p-n junction and the drift current caused by the self-built electric field are equal and in an electrical equilibrium state. When there is a forward voltage bias in the outside world, the mutual suppression of the external electric field and the self-built electric field increases the diffusion current of carriers and causes the forward current. When there is a reverse voltage bias outside, the external electric field and the self-built electric field are further strengthened, forming a reverse saturation current I0 that is independent of the reverse bias voltage value within a certain reverse voltage range. Next, the editor of Ruilongyuan Electronics will explain the working principle of diodes.
How the diode works
The working principle of the diode mentioned here is conductive in the forward direction and non-conductive in the reverse direction. The crystal diode is a pn junction formed by a p-type semiconductor and an n-type semiconductor. A space charge layer is formed on both sides of the interface, and a self-built electric field is built. When there is no applied voltage, it is because the carriers on both sides of the pn junction The diffusion current caused by the concentration difference and the drift current caused by the self-built electric field are equal and in an electrical equilibrium state. When a forward voltage bias is generated, the mutual suppression of the external electric field and the self-built electric field increases the diffusion current of the carriers and causes the forward current. (That is the reason for the conduction) When a reverse voltage bias is generated, the external electric field and the self-built electric field are further strengthened, forming a reverse saturation current that has nothing to do with the reverse bias voltage in a certain reverse voltage range. (This is the reason for non-conductivity) The crystal diode is a pn junction formed by a p-type semiconductor and an n-type semiconductor, and a space charge layer is formed on both sides of the interface, and a self-built electricity is built. When there is no external voltage , The diffusion current caused by the difference in the carrier concentration on both sides of the pn junction and the drift current caused by the self-built electric field are equal and in an electrical equilibrium state. When there is a forward voltage bias in the outside world, the mutual suppression of the external electric field and the self-built electric field increases the diffusion current of carriers and causes the forward current.
When there is a reverse voltage bias outside, the external electric field and the self-built electric field are further strengthened, forming a reverse saturation current I0 that is independent of the reverse bias voltage value within a certain reverse voltage range.
When the applied reverse voltage is high to a certain level, the electric field strength in the space charge layer of the pn junction reaches a critical value, and the multiplication process of carriers is generated, a large number of electron-hole pairs are generated, and a large reverse breakdown current is generated. , Known as the breakdown phenomenon of the diode.
Through the explanation of the working principle of the diode above, everyone has a preliminary understanding and understanding of the basic theoretical knowledge of the diode. In one sentence, the crystal diode is a pn junction formed by a p-type semiconductor and an n-type semiconductor. A space charge layer is formed on both sides of the site, and a self-built electric field is built.
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