Variable resistor (potentiometer) ‐ it is a resistor whose resistance can be changed during operation of the product. It is used to provide the possibility of adjustment (for example, volume in the sound amplifier). The main parameters of the resistor: nominal resistance, tolerance, power, number of channels, rotation angle, shaft design (diameter, type of mounting, etc.).
Instead of variable resistors, for adjustments in digital systems can be used encoders , similar in appearance and method of exposure.
Structural views of variable resistors
Hole mount
Dual variable resistor for mounting in the hole and soldering the contacts to the wire
Such potentiometers are threaded for fastening with a nut into the opening of the housing or chassis.
Contacts are usually designed for soldering to a wire.
For mounting on a board
Vertical type potentiometer for mounting on a printed circuit board
Horizontal type potentiometer for mounting on a printed circuit board
There are vertical and horizontal types: the position of the shaft relative to the surface of the board.
They may additionally have the possibility of fixing with a nut in the hole, as in the previous type.