(d) Name the electrical component represented in Fig 19.18. Fig 19.18
(e) Give one difference between conduction in metals and conduction in semiconductors. (f) What are the charge carriers when electricity flows through a semiconductor?
(g) Sketch a graph to show the variation of current with potential difference for a semiconductor diode in forward bias.
(h) Name the electrical component represented in Fig 19.19. (i) Give two uses of semiconductors.
Fig 19.19
(j) Fig 19.20 shows a circuit used to investigate the variation of current with potential difference for a semiconductor diode in forward bias.
(7) (7)
(7) (7) (7)
(7)
9 V
V
330 A
Fig 19.20 What is the function of the 330 resistor? (7)
‘SECTION B’ FULL ‘STS’ QUESTION
Typical of Question 11 in Leaving Cert. Exam
Q4 Read the following passage and answer the accompanying questions. The operation of semiconductor devices depends on the effects that occur when p-type and n-type semicon- ductor material are in close contact.This is achieved by taking a single crystal of silicon and doping separate but adjacent layers of it with suitable impurities.The junction between the p-type and the n-type layers is referred to as the p–n junction and this is the key to some very important aspects of semiconductor theory. Devices such as diodes, transistors, silicon-controlled rectifiers, etc. all contain one or more p–n junctions.
(a) What is a semiconductor? (b) Name a material used in the manufacture of semiconductors. 344 INVESTIGATING PHYSICS
(‘Physics—a teacher’s handbook’, Dept. of Education and Science) (7) (7)
