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