Semiconductor diodes are used in almost all electronic circuits and play an important role in many circuits.
It is one of the earliest semiconductor devices and is widely used. The crystal diode is a pn structure composed of a p-type semiconductor and an n-type semiconductor. A space charge layer is formed at both ends of the interface, and a self-built electric field is built.
When there is no external voltage, the scattered current caused by the difference in carrier concentration at both ends of the pn structure and the drift current caused by the self-built electric field are equal and in an electrical equilibrium state.
Diodes are used in the diode switch circuit of the patch toggle switch. Because the switching speed of ordinary diodes is not high enough, the diodes used in this switching circuit are special switching diodes. It is an equivalent circuit of the switching diode. The switching diode is equivalent to a switch S1 and has two resistors. The
switch S1 in the equivalent circuit can be considered as an ideal switch, that is, its on resistance is as small as zero, and its off resistance is as large as infinity.
