Potentiometer

Chapter IV

Retrieved on September 1, 2015 from

http://arduino-tutorials.com/wp-content/uploads/2012/01/arduino-potentiometers.jpg

Potentiometer

Today, modernization of technology is rampant. As this process happens, some new electronic devices are invented. It changes the way of our living. It helps a lot on the development of different gadgets for the benefits of the people. People can now choose the appropriate or desired outcome of their appliances or gadgets like controlling the volume or brightness of these. They can now utilize them for the intended purposes. There are many circuit elements that contribute to these developments and one of them is the potentiometer. As defined by the free dictionary by farlex, potentiometer is an instrument used for measuring voltage based on the standard value. It is a resistor containing three terminals with adjustable center connection. It is widely used for volume control in radio and television speakers. It can also be called as pot. The resistive element of potentiometer is made up of different types such as carbon, ceramic, wire wound, and plastic.

 ( http://www.thefreedictionary.com/potentiometer)

Types of Potentiometer According to Composition

1.      Carbon composition

The resistive element is made up of carbon molded on the substrate. It is not expensive.

(http://www.alliedelec.com/images/products/Small/70153180.jpg)

                                                                                                                     

2.      Wire wound potentiometers

It is made up of wounded wires and it is very precise and has long lasting life.

(http://www.aliexpress.com/potentiometer-wire-wound_reviews.html)

3.      Conductive plastic potentiometers

It has high resolution and expensive.

( http://i01.i.aliimg.com)

4.      Cermet

It is very stable and flexible to different levels of temperatures. It is quite an expensive one.

(http://www.partcompany.co.uk/160-thickbox_default/3006p-bourns-34-rectangular-multiturn-cermet-trimpot.jpg)

Types of Potentiometer According to Motion

1. Rotary potentiometers

It is the most common type of potentiometer where the wiper turns in a circular path.

 

Dual-gang potentiometer                Concentric potentiometer                  Multi-turn potentiometer

(http://www.resistorguide.com/potentiometer/)

2. Linear Potentiometers

The wiper moves in a linear pattern by sliding.

Slide potentiometer                  Motorized fader                            Multi-turn linear trimp

(http://www.resistorguide.com/potentiometer/)

3. Digital potentiometers

They are operated and controlled electronically.

(http://www.omega.com/Auto/images/OMDC-DP4_l.jpg)

Application of Potentiometer

1.      It is used for controlling the volume and tone of audio devices.

2.      It controls the brightness of the output of different devices like television and cellphones.

3.      It is used in controlling motion.

4.      It acts as displacement transducers.

Experiment about Potentiometer

Objectives:

            At the end of this experiment, students will be able to

·         manipulate potentiometers using other electrical components

·         calculate the voltage output in different set ups of the pot

·         discuss the importance of flexibility

Materials:

·         potentiometers

·         AC-DC Converter

·         Alligator clips

·         Bulb

Procedure:

1.      Set the potentiometer on the alligator clips.

2.      Attach the bulb on both ends of the alligator clips.

3.      Connect this to the AC-DC Converter

4.      Set up or regulate the voltage.

5.      First, closed the pot in set up 1 and get the voltage drop from different voltage output.

6.      Second, set the pot half-open and repeat procedure no.5.

7.      Third, set the pot fully-open and repeat process no.1

Experimental Data

POT without FIXED RESISTOR        R_BULB= 20 Ω

VOLTAGEOUT (V)	VOLTAGEDROP (v)
	CLOSED POT	HALF-OPENED POT	OPENED POT
3.1 V	2.8 V	1.4 V	0V
5.2 V	4.6 V	2.2 V	0V
7.2V	6.8 V	3.5 V	0V
9.2V	9.0 V	4.3 V	0V
12V	10 V	4.8 V	0V
BRIGHTNESSBULB	BRIGHT	DIM	NO LIGHT

 POT with FIXED RESISTOR; R= 1100 Ω        R_BULB= 20 Ω

VOLTAGEOUT (V)	VOLTAGEDROP (v)
	CLOSED POT	HALF-OPENED POT	OPENED POT
3.2 V	2.2 V	1.1 V	0V
5.2 V	3.9 V	1.8 V	0V
7.4 V	5.8 V	2.7 V	0V
9.4 V	7.6 V	3.8 V	0V
12V	8 V	4.2 V	0V
BRIGHTNESSBULB	BRIGHT	DIM	NO LIGHT

Guide Questions:

1.What do you think is the purpose of the bulb in this activity?

In this activity, the bulb is used as an indicator if there is current or voltage when the pot is open, half open and close.

2. Why do you think the voltage drop is zero when the pot is fully opened and there’s no light in the bulb?

The voltage drop is zero when the pot is fully opened because the pot controls the voltage output.

3. Why do you think there is still voltage when the pot is half-open?

There’s still voltage when the pot is half-opened because the pot allows a certain amount of charges to pass through the circuit.

4. What are the applications of Potentiometer?

Potentiometers are applied in cellphones , television and any other gadgets to control brightness and volume.

Based on the data, the resistance of the potentiometer can be manipulated. Thus, the desired amount of voltage and brightness of the bulb can be achieved.

References:

Retrieved on September 1, 2015 from http://arduino-tutorials.com/wp-content/uploads/2012/01/arduino-potentiometers.jpg

Retrieved on September 1, 2015 from  http://www.thefreedictionary.com/potentiometer

Retrieved on September 1, 2015 from (http://www.aliexpress.com/potentiometer-wire-wound_reviews.html)

Retrieved on September 1, 2015 from http://www.aliexpress.com/potentiometer-wire-wound_reviews.html

Retrieved on September 1, 2015 from  http://i01.i.aliimg.com

Retrieved on September 1, 2015 from (http://www.partcompany.co.uk/160-thickbox_default/3006p-bourns-34-rectangular-multiturn-cermet-trimpot.jpg)

Retrieved on September 1, 2015 from (http://www.resistorguide.com/potentiometer/)
Retrieved on September 1, 2015 (http://www.omega.com/Auto/images/OMDC-DP4_l.jpg)