Rectifier diode

The analogy between the check valve and the diode

The effect of one-sided conductivity is shown depending on the polarity of the diode in the circuit

Rectifier diodes - diodes designed to convert AC to DC . Diodes from semiconductor materials and diode bridges (four diodes in one housing) replaced the vacuum vacuum diodes and ignitrons . Usually, special requirements are not imposed on the speed, capacitance of the pn junction, and stability of the parameters of rectifier diodes ^[1] .

The main parameters of rectifier diodes:

• average forward voltage${\displaystyle {\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">U</span></span>}}_{\text{<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;">avg</span></span>}}}$ {\ displaystyle U _ {\ text {exc.}}} at specified current${\displaystyle {\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">I</span></span>}}_{\text{<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;">avg</span></span>}}}$ {\ displaystyle I _ {\ text {exc.}}} ;
• average reverse current${\displaystyle {\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">I</span></span>}}_{\text{<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;">arr.</span></span>}}}$ {\ displaystyle I _ {\ text {arr.}}} at specified reverse voltage values${\displaystyle {\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">U</span></span>}}_{\text{<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;">arr</span></span>}}}$ {\ displaystyle U _ {\ text {arr}}} and temperature;
• permissible amplitude value of reverse voltage${\displaystyle {\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">U</span></span>}}_{\text{<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;">arr max.</span></span>}}}$ {\ displaystyle U _ {\ text {Sample Max.}}} ;
• average forward current${\displaystyle {\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">I</span></span>}}_{\text{<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;">avg</span></span>}}}$ {\ displaystyle I _ {\ text {exc.}}} ;
• frequency without reducing modes.

The frequency range of the rectifier diodes is small. When converting industrial AC, the operating frequency is 50 Hz, the limit frequency of the rectifier diodes does not exceed 20 kHz.

According to the maximum permissible average forward current, diodes are divided into three groups: low power diodes (${\displaystyle {\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">I</span></span>}}_{\text{<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;">avg</span></span>}}}$ {\ displaystyle I _ {\ text {exc.}}} ≤ 0.3 A), medium power diodes (0.3 A <${\displaystyle {\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">I</span></span>}}_{\text{<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;">avg</span></span>}}}$ {\ displaystyle I _ {\ text {exc.}}} <10 A) and powerful (power) diodes (${\displaystyle {\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">I</span></span>}}_{\text{<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;">avg</span></span>}}}$ {\ displaystyle I _ {\ text {exc.}}} ≥ 10 A). Medium and high power diodes require heat dissipation, so they have structural elements for installation on a radiator .

The parameters of the diodes include a range of ambient temperatures (for silicon diodes, usually from −60 to +125 ° C) and the maximum case temperature.

Among rectifier diodes, Schottky diodes , created on the basis of a metal - semiconductor contact and distinguished by a higher operating frequency (for 1 MHz or more), and a low direct voltage drop (less than 0.6 V), should be highlighted.