Video Transcript
Which of the following correctly
describes a diode? A) A diode is an electronic
component that emits light with a very high efficiency. B) A diode is an electronic
component with a resistance that changes depending on how much light is incident
upon it. C) A diode is an electronic
component that only allows a current to flow in one direction through it. D) A diode is an electronic
component that can be used to amplify signals. E) A diode is an electronic
component with a resistance that changes depending on ambient temperature.
Okay, so in this question, out of
the options A to E, we’ve been asked to select the one that describes a diode. To answer this, it might help to
remember the circuit symbol of a diode. This is how we draw a diode in a
circuit diagram. And this diagram is particularly
helpful to us because, in this diagram, we can see that there’s a little arrow. And we can recall that this arrow
signifies the direction in which conventional current is allowed to flow through a
diode. In other words, conventional
current, that’s current made up of positive charges, can flow in that direction but
is not allowed to flow in the other direction. And that is the functionality of a
diode. In other words then, a diode is an
electronic component that only allows a current to flow in one direction through
it. Hence, that is the answer to our
question.
Very quickly looking at the other
options though, we can see that the description in option A is that a diode is an
electronic component that emits light with a very high efficiency. Well, that type of component is
actually a very specific kind of diode, specifically, a light emitting diode or
LED. And LEDs do actually emit light
with very high efficiency. However, this is not a good
description of a diode in general because not all diodes are light emitting
diodes. And, hence, we haven’t picked
option A as the answer to our question.
Option B says that a diode is an
electronic component with a resistance that changes depending on how much light is
incident upon it. Well, that sounds more like a
description of a light-dependent resistor or an LDR. And so, that’s not the answer to
our question either. Option D says that a diode is an
electronic component that can be used to amplify signals. Well, that sounds very much like an
amplifier, which are often made up of transistors as well as others circuit
components of course. And so, this does not sound like a
description of a diode. And, finally, option E says that a
diode is an electronic component with a resistance that changes depending on ambient
temperature. Well, that circuit component is
known as a thermistor, or sometimes a temperature-dependent resistor. And, hence, option E is also not
the answer to our question.
