Page 146 - Softcopy for Teachers buku kerja + nota Nilam Publications

MODUL • Fizik TINGKATAN 5

Penyelesaian / Solution
(a) (i) Perintang peka cahaya (PPC) / Light-Dependent Resistor (LDR)
(ii) Mengawal voltan tapak secara automatik / Automatically controls the base voltage.
(b) Mengawal dan mengehadkan arus tapak supaya transistor tidak rosak.
Control and limit the base current so that the transistor is not damaged.
(c) (i) Beza keupayaan merentasi V p meningkat
Potential difference across V increases.
p
(ii) Pada waktu malam PPC mempunyai rintangan yang sangat tinggi. Beza keupayaan merentasi PPC sangat tinggi. Maka,
voltan tapak adalah tinggi. Arus tapak mengalir dan ini menyebabkan arus pengumpul yang tinggi mengalir. Transistor
dihidupkan dan mentol menyala.
At night the LDR has a very high resistance. The potential difference across LDR is very high. Hence, the base voltage is high.
The base current flows and produces a large collector current flow. The transistor is switched on and the bulb lights up.
V p R p
(d) =
V XZ R p + R s
10 k Ω
.
. . 2.0 V = 10 k Ω + R s
6.0 V
.
. . 10 k Ω + s = 30 k Ω
.
. . s = 20 k Ω

4 Litar di bawah digunakan sebagai suis kendalian haba.
The circuit below is used as a heat-operated switch.

KBAT
Penyelesaian / Solution
R 5 kΩ
1 (a) (i) Termistor / Thermistor
B (ii)
R 2 A 10 V

C UNIT 4
X
UNIT 4
(b) A: Tapak / Base

B: Pengumpul / Collector
(a) (i) Apakah komponen X? C: Pengeluar / Emitter
What is the component X? 4 V
(ii) Lukis rajah komponen X. (c) (i) R X =
Draw the component X. 5 k Ω + R X 10 V
.
(b) Namakan terminal A, B dan C. . . 10R = 20 k Ω + 4R X
X
.
Name the terminals A, B and C. . . 10R – 4R = 20 k Ω
X
X
(c) Untuk menghidupkan mentol, beza keupayaan . . 6R = 20 k Ω
.
merintangi X mesti paling kurang 4V. . X
In order to light the bulb, the potential difference across . . R = 3.33 k Ω
X
X must be at least 4 V.
(i) Apakah rintangan X apabila mentol menyala? 1 k Ω
What is the resistance of X when the bulb lights (ii) V = (1 + 5) k Ω × 10 V
X
up?
(ii) Apakah yang berlaku kepada mentol X apabila = 1.67 V
rintangan X ialah 1 kΩ?
What happens to the bulb if X has a resistance of V < V
1 kΩ? X minimum
Oleh itu, mentol tidak menyala.
So, the bulb does not light up.

147 © Nilam Publication Sdn. Bhd.