Act as an interpreter. Translate the description of the operation of a semiconductor diode given by your group-mates from Russian into English

19. Translate the text “Types of Diodes” with a dictionary in writing paying attention to the use of Present Simple.

There are several types of junction diodes, which either emphasize different physical aspects of a diode often by geometric scaling, doping level, choosing the right electrodes, or just an application of a diode in a special circuit, or are really different devices like the Gunn and laser diode and MOSFET.

Normal (p-n) diodes are usually made of doped silicon or, more rarely, germanium. Before the development of modern silicon power rectifier diodes, cuprous oxide and later selenium were used. Their low efficiency gives a much higher forward voltage drop (typically 1.4–1.7 V per “cell”) and requires a large heat sink (often an extension of the diode’s metal substrate) much larger than a silicon diode of the same current ratings would require. The vast majority of all diodes are p-n diodes found in some integrated circuits, which include two diodes per pin and a lot of internal diodes.

Avalanche diodes are the ones that conduct in the reverse direction when the reverse bias voltage exceeds the breakdown voltage. These are electrically very similar to Zener diodes, and are often mistakenly called Zener diodes, but the break down has a different mechanism, the avalanche effect. This occurs when the reverse electric field across the p-n junction causes a wave of ionization, reminiscent of an avalanche, leading to a large current. The difference between the avalanche diode (which has a reverse breakdown of above about 6.2 V) and the Zener diode is that the channel length of the former exceeds the “free path” of the electrons, so there are collisions between them on the way out. The only practical difference is that the two types have temperature coefficients of opposite polarities.

There also exist crystal diodes, constant current diodes, Esaki or tunnel diodes, gun-diodes, light-emitting diodes (LEDs), laser diodes, photodiodes, etc.

Indicators such as some "magic eye" tubes and the type 6977 fluorescent-anode type have glowing electrodes.

In Russian write a content-based summary of the text you have translated.

Make a reverse written translation (from Russian into English) of your summary.

22. Find more information about conduction of current in a semiconductor diode and tell your group mates.

UNIT II

Language Work

Present Continuous