We can imagine that a runner a sliding mechanism by hand via a mechanical transmission in different places is pressed against a resistance course this is raising so different resistance values.
Such a potentiometer usually have a rotation of 270 degrees and is used in such a way that with the runner against the left attack the voltage at the output is 0 and with the runner against the right attack the voltage at the output the highest value is reached.
That is reflected in, for example, your radio links to no sound and right to much sound.
You have a point on a pot A = starting position of the runner = 0 degrees and point E = end position of the runner = 270 degrees and the branch where the runner is connected with S indicated often the expressions A-E-S also on the potentiometer.
Also there are so-called trim or setting potentiometers these are then usually soldered directly into a circuit or a print.
Then you can with a screwdriver set that is inserted in the sparing the runner moving segment and thus a certain resistance value.
There are also dual potentiometers, you can find back in stereo radios to send both the left and right channel.
And also you can find these in some car radios back then, but now with the function, for example, to regulate the volume and balance.
That is then realized by without depressing the button to set the front potentiometer and thus to set the desired volume, and if one then the button and turns the rear to set the activated balance potentiometer.
Disadvantage is that you then to the State of the button can't see how both potentiometers are set.
There are also the screw potentiometers.
The runner of this is by a long screw operated.
With the advantage that the adjustment of this very accurate.
And then not to forget we still have the sliding potentiometer this actually works exactly the same as the well-known potentiometer.
Just slide your now in the length direction.
The use of the potentiometer in practice in electronics are often set up all kinds of line processes have to be carried out first of all that we make distinction between setting mechanisms potentiometers that can be operated from the outside, allowing the user to certain features, such as the volume, voltage, channel choice and the like can set.
And, on the other hand, potentiometers that are needed to build a circuit to set a certain function correctly.
That may need to tolerances of components by means of a rheostat a trim potentiometer.
Also, when a transistor that part is more often turn the work point can be set very accurately.
Also there is a line resistance.
Must have a photo element to turn on a lamp at a given exposure strength? then this can switch-on point also by means of an adjustable resistance are fixed.
Well as far as this part about the adjustable resistance.
