Skip to main content

Root Mean Square Current (I rms)

Root Mean Square Current

As mentioned in the previous post, the value of AC is always changing. Then, how do we measure its value??? We could not use the maximum value of the current Io, because it only occurs at a moment. The average current is ZERO. Hence, one effective value that we could use the root mean square value. Irms. The formula for  Irms is given by:
where Io is maximum current.

Irms is the value that is equivalent to a steady direct current. We can investigate this by comparing 2 circuits containing lamp each. circuit 1 uses battery as the source, while circuit 2 uses a.c. supply. AC supply is adjusted so that both lamps are equally bright. At this point, DC and AC supplies are transferring energy to the lamps at the same rate (Power). By equating the Power of both circuits, we can deduce the equation of Irms as above.Therefore, the d.c. voltage equals the r.m.s. value of the a.c. voltage. 

 From the the graph below and the equation of Irms above, we will notice that the r.m.s. value is about 70% of its maximum value. 
                                                       



Thank you,
Mdm Ummi Atiah KMPk
~ May it Benefits You ➽💕
Labels:

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