Skip to main content

Potentiometer

Potentiometer

Potentiometer is a device that is equivalent to a circuit. It actually applies the same concept as that of
potential divider. Do you still remember the principle of potential divider? If not, please refer here.

Physically, this is how a potentiometer looks like ( one example):


Normally we use the variable resistor as the potentiometer to control the voltage. Before I explain any further, please refer Diagram 1 and Diagram 2 below:

Diagram 1: Potential Divider

                                 
Diagram 2: Potentiometer

If we could realize, both Diagram 1 & Diagram 2 are quite similar. In Diagram 2, we have that black thick wire of from A to B. As we know, the resistance of any wire is always directly proportional to wire which means that , the longer the wire the higher the resistance. 

l directly proportional with R

In the middle of wire AB, we have S. S is where we can control in order to get our desired resistance. The chosen amount of resistance is then contributes to the potential difference across voltage,Vout (measured by a voltmeter). S divides wire AB into portion AS and SB. Did you get this?? Remember l directly proportional with R, hence 

                                                                                    lAS = RAS

                                                                                       and 

                                                                                     lSB = RSB

Recally equation for voltage divider, 

VAB = RAB 


The purpose of a potentiometer is to determine the unknown value of emf or the unknown value of the internal resistance of the same source (emf). 

Referring to Diagram 2, if we replace Voltmeter (that measures Vout ) with a cell with unknown emf, we could apply equation __ to know the answer.  


Thank You, 
Mdm Ummi Atiah
KMPk

                                                                 ~ May it Benefits You ➽💕

Comments

Post a Comment

Popular posts from this blog

Concept Mapping

Salam 'alaik,  InshaAllah, today I would like to share about what I've been learning from my Master course that is CONCEPT MAPPING. We did it practically during the lesson, not just learning it by theory. This hands on experience really intrigued me.  Concept Mapping is a verb.  It is  a way to connect the knowledge of certain topics based on its concepts while Concept Map is a noun where  it is a type of graphic organizer used to help students organize and represent knowledge of a subject.  Concept maps  begin with a main idea (or c oncept ) and then branch out to show how that the ideas are connected to the other ideas. In order to link the concepts, we need to start a sentence by a quantity and end it also by a quantity.  Our lecturer, Dr NurulHuda had introduced a website  where we able to apply doing concept map. We practiced using this software by applying 2 topics. The first concept map is for the States of Matter and the second one is for the Trend in Educationa
Post a Comment
Read more

Smart Classroom

Assalamualaikum & Hi everyone! The first time I enter a classroom for my technology & innovation in physics course in university, it intrigued  me. The classroom is facilitated with devices which hence called as smart classroom. Here I attach several snaps of the view of it, also featuring my lovely course mates & lecturer :) Smart Wall , Smart TV & Dr Nurul Smart Wall & Smart TV + Farah & me 💙 Smart Wall & Smart TV + Roza(from Aceh) & me 💙 Smart Classroom + K. Kamalia & Mira 💙 The idea of this classroom beautiful!The walls are painted at particular area which provides unlimited spaces for teachers to scribble on. It reminds me of how I always advise my students to have separate answer sheet every time they work on the worksheet. They are forbidden to write their answer or ideas for the answer near the question as they kind of limit their thoughts.  My reason is always be that the more space we have, the greater the idea we
Post a Comment
Read more

Capacitors

Capacitors Capacito r is a device that is normally used in electrical appliances such as radios, computers and TV. There are many different types(looks) of capacitors as shown below: The function of the capacitor is to store electrical charges. Remember , we have 2 types of charges ( positive and negative). Once the capacitor has stored the charge, it can release electrical energy. I give you an example: The flash unit of camera also uses a capacitor. The fact that the camera can give out the flash, it is actually releasing the energy from the charge that is stored in the capacitor. When we measure something , it must has its own quantity and unit. For example, (i) the length (quantity) of a ruler --> the unit is metre (ii) the mass  (quantity) of a ball --> the unit is  kg Same goes to the capacitor, the quantity measured by the capacitor is capacitance and its unit is Farad.  Scientifically, the meaning of capacitance is the ratio of the amount of  charge
Post a Comment
Read more