Potentiometer - This handy little unit that you need to know how to use.
It is often used in circuits, such as for example - control the volume of music equipment, light control brightness and more.
If you are not familiar with the potentiometer, in the beginning it may seem that it is difficult to understand. But it is not so. See connection examples at the end to see it in action.
What is the pot?
At its core - it's resistor. But if the value of the resistor classic remains unchanged in the case of the potentiometer you can change the resistance by turning the engine.
It has three terminals and the symbol is as follows:
Between the two lateral contacts potentiometer strip is resistive material. For example, such as carbon. This material provides a resistance.
We call the average contact - sliding contact.
When moving the cursor to the left the resistance between the middle and left contacts decreases. And the resistance between the middle and right contacts increases.
Move the slider to the right, and the opposite will happen.
When you buy a pot, you have to select. Example 100 ohms. This value is between the two extreme resistance contacts. And this is the most important resistance which you can get from him.
Connection example № 1: Variable resistor
If you need a simple resistor, the resistance of which you want to change, you need only two pins: the average and one of the side.
The picture above shows a simple circuit for LED control. Additional resistor is designed to ensure that you do not put out the light-emitting diode, even if you change the resistance of the potentiometer to zero.
Turn potentiometer shaft in one direction, and the resistance increases. Rotate it in the other direction, and the resistance decreases.
Connection Example №2: strange connection
Sometimes you see a potentiometer on the concept that is connected as follows:
Middle and bottom contacts are connected. What for?
And how does this affect the resistance?
This method of connection is actually connected to only two pins. Connecting to the middle of the third contact pin does not affect the resistance in general.
So why do it?
It's simple - some people prefer to just such a connection because of the nature of their schemes.
Connection example № 3: Volume input
This example uses all three of the potentiometer contact to create a simple method for adjusting the volume of the amplifier.
Plug it in such a way, you get voltage divider which reduces the input voltage. The more you turn the engine, the more you reduce the volume.
The implementation of such a scheme with the potentiometer is very common in audio equipment.