Video Transcript
Which of the following is the
correct circuit symbol for a variable resistor? Is it option (A), (B), (C), (D), or
(E)?
The question asks us to identify
the symbol for a variable resistor. We know that a variable resistor is
a type of resistor with a resistance that can be changed, often by turning a knob or
using a slider. Let’s look at each of the symbols
provided in the question and choose one. The symbols used for components in
electrical circuits can sometimes be chosen logically, as their design often relates
to their function or structure.
Option (A) is a symbol representing
a resistor. We might say that the symbol
resembles a wire that forms part of a circuit that is in the shape of a zigzag. If it makes the symbol easier to
remember, we could think of how the symbol relates to a typical basic resistor,
which might be a long nichrome wire wrapped around a ceramic tube, which from the
side looks a little like a zigzag.
The symbol for (B) is a light bulb,
which is an X inside a circle. If we want a way to remember this,
we might imagine that the circle represents the glass bulb and the X represents the
glowing filament inside the bulb.
The symbol for (C) is the same as
for a resistor, but with an arrow through it. And this is the symbol for a
variable resistor, which is what we are looking for. The symbol makes sense, and if we
want a way to remember it, we could think that the arrow represents the ability to
change the resistance.
(D) is a symbol with two vertical
parallel lines, one thicker and shorter and another thinner and longer. These represent the negative and
positive terminals, respectively, of a cell, a source of electrical power in
circuits.
The symbol for option (E) is two
cells separated by a dashed line and indicates that there are two or more connected
cells forming what we call a battery. Batteries are made up of multiple
cells and are used to power electrical devices.
So to recap, the correct answer is
option (C), variable resistor.
