1. Twenty Questions
Electronics

2. Twenty Questions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

3. Resistance has decreased as the current has increased.
1. At the start of the experiment, the ammeter reading is 0.02A, at the end it is 0.15A
Explain whether the resistance of the component show has increased or decreased.
Resistance has decreased as the current has increased.
I=V/R, where V is constant.

4. 2. Of what 3 main parts does an electronic system consist?
Input
Process
Output

5. 3. Name the component & explain how it works.
Thermistor
Temperature Up
Resistance
Down

6. 4. Select suitable input and output devices for a baby monitor.
Input – Microphone
Output - Loudspeaker

7. 5. Give 3 analogue input devices
Dimmer switch.
Volume control on radio.
Heat dial on cooker.

8. 6. What is in decimal? 5

9. 7. Name & state the function of the component.
Transistor
Electronic switch which automatically switches ON at 0.7V.

10. Less heat produced. Lower energy usage. Smaller.
8. Why would you use an LED instead of a filament to indicate that an electrical appliance was switched on?
Less heat produced.
Lower energy usage.
Smaller.

11. 9. Calculate the current if the light level is 25lux.
Resistance 15
120 20 80 25 60
I = V/R
I = 9/60
I = 0.15A

12. 10. How can the frequency of a clock pulse generator be increased?
Decrease the value of the capacitor
Decrease the value of the resistor.

13. 11. Name the component & explain how it works.
LDR (light dependent resistor)
Light Up
Resistance
Down

14. 12. Give the energy change for the following.
Solar cell
Microphone
Thermistor
LDR
Light Electrical
Sound Electrical
Heat Electrical

15. 13. The LED has a voltage 2V. What is the value of R?
VR = 12-2 =10V
R = VR / I
= 10/2.5
= 4Ω

16. 14. Give an example of a time delay circuit.
Interior light in car staying on for a few seconds after the door has been closed.

17. 15. What is 6 in binary?

18. 16. What happens to the value of V2 as R1 increases?
V2 decreases

19. 17. If R1=10kΩ and R2=2.5kΩ calculate V2.

20. 18. Which component does the graph represent?
Voltage
18. Which component does the graph represent?
Capacitor.

21. 19. Name the type of device which produces the output shown.
Digital

22. 20. Give the energy change for the following.
Electrical Light
Electrical Kinetic
Electrical Sound
LED Solenoid Relay Loudspeaker