As already mentioned, there diodes assembled from two small crystals, one of whom p and the other is n-doped.



The n-doped crystal, the flow of electricity through the movement of electrons instead, whereas in p-doped part of conducting electricity predominantly by the positive charges (also described as holes) takes place.



Electrons and holes are located in the crystal lattice between two atomic nuclei.



By coincidence of the two crystals, a transition, this is logically pn-called transition.



Here electrons from the n-p field in the area and fill the holes. This process takes place vice Versa instead. The narrow area in which this process takes place, cargo space is called zone.



The space charge zone and the resulting electric field is not widespread in the entire crystals, because the layer acts as an insulator and prevent a further diffusion. The voltage is anti-called diffusion tension and must be at a nearby stream in the direction of passage only to be overcome and will be called Forward voltage (values: 0.65V silicon germanium: 0.25 V).



The special is that the boundary layer by the voltage can be controlled.



When the diode to a circuit that n-plus range and p-minus range, the insulating effect and the space charge zone is widened to include the inner resistance of the diode. The capacity between anode and cathode, however, be reduced.



Polt is now the tension around, so n-minus area and p-plus range, the influx of electrons in the n-field disgusted and have no other way than by the p-area to hike. So it flows through the power diode. The diode is, however, only conductive when the Forward voltage is exceeded.