Diode (English: Diode), an electronic component, a device with two electrodes, allowing only the current flowing through a single direction. Many use is to apply its rectification function. The variable capacitance diode (Varicap Diode) is used as an electrically adjustable capacitor.
Most diodes have the current directivity we usually call the "rectifier (Rectifying)" function. The most common function of diodes is to allow only the current to be passed by a single direction (called a forward bias), which is reversed when blocking (called inverse bias). Therefore, the diode can be converted into an electronic version of the counter valve. In fact, however, diodes do not exhibit such a perfect opening and closing directionality, but rather complex nonlinear electronic features — which are determined by a specific type of diode technology. Diodes are used in addition to the way they are used as switches, there are many other functions.