There are two types and three classifications of resistors.
You are correct.
We've already discussed one classification of resistors. That was the fixed resistor. The next
classification is the tapped resistor. This resistor is manufactured with a fixed value of resistance from end to end
having either fixed taps placed at intervals on the resistor that will give fixed resistances, or an adjustable tap that
can be secured on the resistor when the desired ohmic value has been established. Below are examples of the
fixed-tap and adjustable-tap resistors and their schematic symbols.
The last classification of resistors is the variable resistor. It can be either metallic or nonmetallic. It is
constructed to be continuously variable from zero to its maximum resistance. Below are two cutaway examples
of variable resistors and the schematic symbol for a variable resistor.
The three classifications of resistors are
fixed, tapped, and metallic
metallic, nonmetallic, and variable
fixed, tapped, and variable