Page 691 - SUBSEC October 2017_Neat

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Item 20 refers to the following diagrams.

A A
a.c a.c
supply R CR01 supply R CR02

B
B
Figure 1 Figure 2

20. Which of the following traces will be Item 21 refers to the following diagram.
seen on the cathode ray oscilloscopes in
Figure 1 and Figure 2? +20V

Thermistor
(A) A

200Ω

0V

(B)

21. The potential divider above is formed
from a thermistor and a 200 Ω resistor.

The thermistor has a resistance of 2 kΩ
at room temperature and 200 Ω at 100 0C.
(C)
What is the change in the potential at A
when the thermistor is moved from
water at room temperature to boiling
water?

(D) (A) Rise of about 8V
(B) Fall of about 8V
(C) Rise of about 18V
(D) Fall of about 18V

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02238010/SPEC 2017