Semiconductor Diodes

Q34. What type of diode has orange, blue, and gray bands?

A34. 1N368.

Q35. What is the greatest threat to a diode?

A35. Heat.

Q36. When checking a diode with an ohmmeter, what is indicated by two high resistance measurements?

A36. The diode is open or has a high-forward resistance.

Q4. State one requirement of an electron tube, which does not exist for semiconductors, that makes the tubeless efficient than the semiconductor.

A4. The electron tube requires filament or heater voltage, whereas the semiconductor device does not; consequently, no power input is spent by the semiconductor for conduction.

Q5. Define matter and list its three different states.

A5. Anything that occupies space and has weight. Solid, liquid, and gas.

Q6. What is the smallest particle into which an element can be broken down and still retain all its original properties?

A6. The atom.

Q7. What are the three particles that comprise an atom and state the type of charge they hold?

A7. Electrons-negative, protons-positive, and neutrons-neutral.

Q8. What is the outer shell of an atom called?

A8. The valence shell.

Q9. What term is used to describe the definite discrete amounts of energy required to move an electron from a low shell to a higher shell?

A9. Quanta.

Q1. What is a solid-state device?

A1. An electronic device that operates by virtue of the movement of electrons within a solid piece of semiconductor material.

Q10. What is a negative ion?

A10. A negatively charged atom having more than its normal amount of electrons.

Q11. What is the main difference in the energy arrangement between an isolated atom and the atom in a solid?

A11. The energy levels of an atom in a solid group together to form energy bands, whereas the isolated atom does not.

Q12. What determines, in terms of energy bands, whether a substance is a good insulator, semiconductor, or conductor?

A12. The width of the forbidden band.

Q13. What determines the chemical activity of an atom?

A13. The number of electrons in the valence shell.

Q14. What is the term used to describe the sharing of valence electrons between two or more atoms?

A14. Covalent bonding.

Q15. Name the two types of current flow in a semiconductor.

A15. Electron flow and hole flow.

Q16. What is the name given to a piece of pure semiconductor material that has an equal number of electrons and holes?

A16. Intrinsic.

Q17. What is the name given to a doped germanium crystal with an excess of free holes?

A17. P-type crystal.

Q18. What are the majority carriers in an N-type semiconductor?

A18. Electrons.

Q19. What is the purpose of a PN junction diode?

A19. To convert alternating current into direct current.

Q2. Define the term negative temperature coefficient.

A2. It is the decrease in a semiconductor's resistance as temperature rises.

Q20. In reference to the schematic symbol for a diode, do electrons flow toward or away from the arrow?

A20. Toward the arrow.

Q21. What type of PN diode is formed by using a fine metal wire and a section of N-type semiconductor material?

A21. Point-contact.

Q22. What are the majority carriers in a P-type semiconductor?

A22. Holes.

Q23. Conduction in which type of semiconductor material is similar to conduction in a copper wire?

A23. N-type material.

Q24. What is the name of the area in a PN junction that has a shortage of electrons and holes?

A24. Depletion region.

Q25. In order to reverse bias in a PN junction, what terminal of a battery is connected to the P material?

A25. Negative.

Q26. What type of bias opposes the PN junction barrier?

A26. Forward.

Q27. What is a load?

A27. Any device that draws current.

Q28. What is the output of a half-wave rectifier?

A28. A pulsating dc voltage.

Q29. What type of rectifier is constructed by sandwiching a section of semiconductor material between two metal plates?

A29. Metallic rectifier.

Q3. Name three of the largest users of semiconductor devices.

A3. Space systems, computers, and data processing equipment.

Q30. What type of bias makes a diode act as a closed switch?

A30. Forward bias.

Q31. What is used to show how diode parameters vary over a full operating range?

A31. A characteristic curve.

Q32. What is meant by diode ratings?

A32. They are the limiting values of operating conditions outside which operations could cause diode damage.

Q33. What does the letter "N" indicate in the semiconductor identification system?

A33. A semiconductor.