Why potentiometer 3 pins

Viewed 4k times. I'm talking about this sort of thing from here : simulate this circuit — Schematic created using CircuitLab Rather than this from here : simulate this circuit Please ignore resistance values, just examples. Community Bot 1.

TCassa TCassa 6 6 silver badges 16 16 bronze badges. Once you've decided you want a current limiter, the reason for the decision to connect the wiper to the otherwise-unconnected end is as answered by Jasen. JlM claimed that the connection btw pins 2 and 3 "makes the potentiometer into a variable resistance". No, it does not do that! The pot is being used as a variable resistance in that circuit whether or not there's a connection btw pins 2 and 3.

Add a comment. Active Oldest Votes. Jasen Jasen Its make-and-break characteristic could cause erratic behavior in the rest of the circuit. By connecting the slider to the other end, a minimum current is maintained does not go to zero , as the slider breaks its contact. Sign up or log in Sign up using Google. Sign up using Facebook. Although it didn't quite make sense to me at first, i stumbled upon this page that gives information about voltage dividers.

Sparkfun : Voltage dividers. Since a potentiometer consists of two resistors, just like the most basic voltage divider you see two or three resistors along a wire, they cut voltage each time it can be used as a voltage divider. A 3 terminal pot used with 3 terminals, is basically just a voltage divider. As you move the wiper, you increase one resistor in the voltage divider, while decreasing the resistance in the other.

So a 3 terminal pot is a variable voltage divider. But each section of the voltage divider can be considered to be an infinite number of resistors in series such that the total sum is the pot full scale resistance.

Now if we use this infinite resistor model, if you connect one leg of the pot and place in somewhere in within this infinite set, that means we have shorted out those resistors.

The total resistance from end to end is no longer the full scale pot resistance because we have shorted out some of those "resistors". You don't have to connect one the wiper to ground. So long as the wiper is connected to one leg of the potentiometer, it will behave a variable resistor. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Learn more. Ask Question. Asked 6 years, 8 months ago. The most common form is the simple linear taper.

In a linear taper, the relationship between the resistance and the potentiometer position is linear. This means that if the knob of the potentiometer is at the medium position, the output voltage is half of the voltage through the potentiometer.

See the figure below:. Non-linear tapers are specially used in audio control applications, namely logarithmic tapers there are also inverse-logarithmic tapers. The relationship between the position and the resistance is shown in the following figure:.

Arduino Step-by-Step Projects » Build 25 Arduino projects with our course, even with no prior experience! Very nice article and full of great information. Thank you so much! I wish more information on the Web was well presented like this. Many Thanks. Obrigada pelo seu elogio. Cumprimentos, Sara. Notify me of follow-up comments by email. Notify me of new posts by email.