Overvoltage protection

Diodes are frequently used to conduct damaging high voltages away from sensitive electronic devices. They are usually reverse-biased (non-conducting) under normal circumstances. When the voltage rises above the normal range, the diodes become forward-biased (conducting). Many integrated circuits incorporate diodes on the connection pins to prevent external voltages from damaging their sensitive transistors. Specialized diodes are used to protect from overvoltages at higher power.

Ionizing radiation detectors

Semiconductor diodes are sensitive to more energetic radiation. In electronics, cosmic rays and other sources of ionizing radiation cause noise pulses and single and multiple bit errors. This effect is sometimes exploited by particle detectors to detect radiation. Some of these detectors sense position as well as energy. They have a finite life, especially when detecting heavy particles, because of radiation damage. Semiconductor detectors for high-energy particles are used in large numbers.

Current steering

Diodes will prevent currents in unintended directions. To supply power to an electrical circuit during a power failure, the circuit can draw current from a battery. An uninterruptible power supply may use diodes in this way to ensure that current is only drawn from the battery when necessary.

Vocabulary

4. With your group, match the following words and word combinations with their definitions.

1) Diode logic

2) Power conversion

3) Overvoltage protection

4) Radiation detection

5) Demodulation

6) Temperature measurement

7) Current steering

a) converting a modulated carrier wave into a current equivalent to the original signal.

b) using a p-n junction for temperature determining.

c) changing alternating current into direct current or vice versa.

d) constructing Boolean logic gates from diodes acting as electrically operated switches.

e) protecting electrical devices from voltage spikes.

f) detecting the presence and sometimes the amount of radioactive particles and waves.

g) preventing currents in unintended directions.

5. With your group, give all possible definitions of a “diode” taking into account its applications.

Writing

6. With your group, write the Diode applications section. Use all the information from the previous tasks. Each group member should work on different stages. Check and correct each other’s work before you complete. Use this plan to help you.

Diode applications

1) Radio demodulation

2) Temperature measurement

3) Diode logic

4) Power conversion

5) Overvoltage protection

6) Ionizing radiation detectors

7) Current steering

Review

Make a crossword puzzle on the topic: “Diodes

UNIT 3

TRANSISTOR

Fig.3.1 A typical transistor on an electronic circuit board.

Contents

Ø What Does a Transistor Actually Do?

Ø Types of Transistors and How They Work.

Ø Transistors in Computers.

Ø Who Invented the Transistor?