Chapter 44 - Electronics

Question 1

Diode

Answer 1

A device that allows an electric current to flow in one direction only

Question 2

A diode conducts only when the ‘P’ terminal of the diode is connected to the _______ of the battery. The diode is now in _______ ______

Answer 2

A diode conducts only when the ‘P’ terminal of the diode is connected to the POSITIVE of the battery. The diode is now in FORWARD BIAS

Question 3

A diode will not conduct when the ‘P’ terminal of the diode is connected to the _______ of the battery. The diode is now in _______ ______

Answer 3

A diode conducts only when the ‘P’ terminal of the diode is connected to the NEGATIVE of the battery. The diode is now in REVERSE BIAS

Question 4

What is a LED?

Answer 4

Light-emitting diode: a diode that gives out light when current passes through it

Question 5

A LED will only emit light when…

Answer 5

…it is in forward bias

Question 6

A LED will not emit light when…

Answer 6

…it is in reverse bias

Question 7

Why is a resistor always placed in series with a LED?

Answer 7

A LED only uses a very small current to emit light.If a large current flows through a LED it will likely burn out. Therefore, a resistor is placed in series with the LED to limit the current through the diode

Question 8

What is a LDR?

Answer 8

Light-dependent resistor: resistor whose value of resistance can change as the intensity of the light falling on it changes

Question 9

If a bright light falls on a LDR…

Answer 9

…resistance is low and a larger current can fall through the resistor

Question 10

If a dim light falls on a LDR…

Answer 10

…resistance is high and a smaller current will fall through the resistor