Rectifier diodes

Junction semiconductor diode

A semiconductor junction diode is a device - most often made of silicon - that uses the so-called PN junction. It is an interface between two regions of a semiconductor, doped P-type or N-type. Doping a semiconductor is intended to create electrical imbalance in it by changing the concentration of carriers.

In the case of a semiconductor doped to the P type - positively - the concentration of positive carriers - holes - is increased, and in the case of a semiconductor doped to the N type - negatively - the concentration of negatively charged carriers - electrons - is increased. Current can only flow through such a connector in one direction, thanks to which the diode will "rectify" the signals.

Typical operating systems of rectifier diodes

Semiconductor diodes used as rectifiers most often operate in one of two basic systems - a half-wave rectifier or a two-wave rectifier (full-wave). In a half-wave rectifier, only the positive or negative half of the wave is conducted and the other half is blocked.

Rectifier diode - additional information

Since only half of the input wave reaches the output, the average output voltage of such a system is lower than the input voltage. Half-wave rectification requires a single diode in a single-phase system or three in a three-phase system. These rectifiers produce pulsating DC current with a high level of ripple and need much larger filters to eliminate noise from the output.

In turn, a full-wave rectifier converts the entire input waveform into direct current - it uses both halves of the input sine wave and gives a higher average voltage at the output. It consists of four (for a single-phase system) or six (for a three-phase system) diodes in the so-called configuration. Graetz's sternum. The two-wave rectifier offers much lower output ripple.

The most important parameters of the rectifier diode

The rectifier diode is characterized by many parameters, but only a few of them are needed to properly select it for our system. First of all, you need to pay attention to the maximum allowable operating voltage and the maximum diode current (i.e. the maximum forward current). For comparison, germanium diodes have a lower permissible reverse voltage. Moreover, they are characterized by a lower permissible junction temperature compared to silicon diodes.

These parameters cannot be exceeded in the system so as not to damage the rectifier diodes - it is good to choose diodes with higher parameters to have some reserve. Additionally, it is worth paying attention to the maximum instantaneous current, repeatable reverse voltage and repeatable forward current of the diode.

Next, it is worth checking the voltage drop on the diode (in the forward direction) - this value, multiplied by the flowing current, will give us the power losses that will be converted into heat on the element - they cannot exceed the maximum permissible level of power losses on the diode , otherwise it will burn during operation.

Our store's assortment includes a wide selection of rectifier diodes with various permissible high currents. The maximum allowable reverse voltage (peak operating reverse voltage) and the maximum junction temperature depend on the specific model. We offer silicon diodes from renowned manufacturers used, among others, in electronics. All products come directly from manufacturers or proven suppliers. In addition to rectifier diodes, we also offer a wide selection of laser diodes , IR diodes and RGB LEDs .