A rectifier diode is an electronic device designed to convert alternating current into direct current. This is such a two-electrode device, which has only one-sided (unipolar) electrical conductivity. The rectifier diode made of semiconductor materials and the so-called diode bridges (when four diodes are connected diagonally in pairs in one housing) replaced the ignitron and the electrovacuum diode.
The effect of rectifying an alternating current and converting it to a direct one arises at the semiconductor-metal, metal-semiconductor transition, or in the so-called electron-hole transition in some crystals (for example, silicon, germanium, selenium, copper oxide). Such crystals often serve as the basis of the device.
A semiconductor rectifier diode is used in radio engineering, in electronic and electrical devices. In fact, rectification is the conversion of alternating current (voltage) into a current of one polarity (pulsating constant). This type of rectification in engineering is necessary for opening and closing electrical circuits, switching and detecting electrical signals and pulses, and for many other similar transformations. Such characteristics of the diode as speed, stability of parameters, capacitance of pn junctions do not oblige to impose any special requirements on themselves.
Such a device has certain electrical parameters and characteristics of diodes:
- forward voltage at the indicated current value (the average value is taken ) ;
- reverse current at a given value of reverse voltage and temperature (average value) ;
- amplitude permissible values for the maximum reverse voltage;
- the average value of the direct current;
- the value of the frequency without reducing the mode;
- resistance.
The rectifier diode is often abbreviated simply as a rectifier. As a component of an electric circuit, it has a high resistance to current that flows in one direction, and low to that that flows in the opposite direction. This causes rectification of the current.
A device such as a rectifier diode has a fairly small frequency range. The operating frequency for industrial use of such a device when converting AC to DC is 50 Hz. The limiting frequency is considered to be no more than 20 kHz.
The rectifier diode as an electronic device can be divided into several groups according to the value of the maximum average forward current. This is a diode of low power (up to 0.3 amperes), medium power (from 0.3 A to 10 A) and heavy duty (power) rectifier diodes (more than ten amperes).
The main parameters of such an electronic device as a rectifying diode must also include the operating range for the ambient temperature (usually it ranges from -50 to +130 degrees Celsius for the most common type of diode - silicon) and the maximum case temperature (a variety of parameters, in depending on capacity, destination and manufacturer).