There are many types of passive electronic components. A 1. works as a one-way switch, i.e. allowing current to flow in one direction, and also as a 2. , changing AC into 3. . Both are used in circuits needing constant voltage control. An LED (Light Emitting Diode) is instead used in 4. . A resistor opposes 5. and protects circuits from damage. It is used in 6. instruments, voltage 7. and amplifiers. An 8. , when current flows through it, creates a variable 9. field. It 10. AC but allows DC to flow and is used in 11. , electric motors and high-frequency 12. circuits. A capacitor temporarily 13. electrical energy allowing only AC to flow, and is used in electronic circuits as a 14. .
11.1 Listen to the recording about LEDs and decide if the sentences are true (Vero) or false (Falso).
1. LEDs are very common in our world.
2. LEDs are types of diodes which emit light.
3. Diodes allow current flowing in two directions.
4. An LED consists of two components, an anode and a cathode.
5. The anode and the cathode are the positive and the negative wire respectively.
6. LEDs emit light thanks to a semiconductor inside them.
7. The colour of the light depends on the colour of the LED housing.
8. An LED has components devised to direct its light and protect it.
9. LEDs are used both as light sources and indicators.
10. LEDs do not produce heat at all.
11. High temperatures cause the degradation of the semiconductor inside the LED.
12. The life span of an LED can be increased by using a heat sink.
11.2 Correct the false sentences from the previous exercise.aperta
Soluzione suggerita:1. True; 2. True; 3. False, They only allow current to flow in one direction; 4. False, LEDs consist of three components: an anode, a cathode, and a semiconductor crystal in between; 5. False, They are the negative and the positive wire respectively; 6. True; 7. False, It depends on the type of semiconductor material employed in it; 8. True; 9. True; 10. False, They produce a significant amount of heat; 11. True; 12. True.
12.1 Write the main function of a diode.aperta
Soluzione suggerita:It conducts electricity in one direction only.
12.2 Write the main function of a capacitor.aperta
Soluzione suggerita:It stores electricity in an electronic circuit.
12.3 Write the main function of a resistor.aperta
Soluzione suggerita:It controls or blocks the flow of current.
12.4 Write the main function of a inductor.aperta
Soluzione suggerita:It blocks AC current while letting DC current flow.