Basic Law (Series and Parallel Resistors)

It’s been another week! And here we are again with our weekly dose in everything about circuits. Every little thing is so important that we have to master every bit of it. Specially on the prelude part, or the introduction parts, the basics is at most priority. The basic laws, as our beloved professor would say, without mastering these basic laws, we will have difficulties on the future matters.

The first law that we learned is the series resistor connection or simply put series connection. A connection is said to be series if the current is flowing on a single path and has the same amount through the connection. And we also learned that (although it was then thought on our physics class, but it is good that we have some refreshment of such) in a series connection, it will have the same current flowing on it, but it will have different voltages across each resistors. Thus we learned about voltage division. Voltage division is the formula (at least that is what we know of it) that can accurately solve for each of such voltage across resistors. It is written in V1=VR1(R1+R2), where “R” is a the amount of resistance a resistor and “V” obviously is a voltage. To solve for equivalent resistance (Req) for a series connection, here is the formula, Req=R1+R2 … . And often we only use the ohm’s law to solve for voltage, resistance and current.

Series connection is as illustrated as follows.




The second law that we learned is the parallel resistor connection or simply put parallel connection. A connection is said to be parallel if the voltage flowing is common across the connection. Also the current flows in two or more path along the connection. As said, the voltage across each resistors are the same, but the current flowing on each will have different values thus we have been introduced to the current division. Current division is a formula (or at least that is what we know of it) that can accurately solve for each of such current across resistors. It is written in I1=IR2/(R1+R2), where ”R” is a the amount of resistance a resistor and I is obviously the current. To solve for its equivalent resistance (Req) of a parallel connection the formula to be used is, 1/Req=1/R1+1/R2 … . And the used formula to solve for any voltage, current, resistance is the Kirchhoff’s Voltage Law(KVL) and Kirchhoff’s Current Law(KCL).

Parallel connection is as illustrated as follows.

Learning:

Another basic we have to master. Knowing the current flow to each elements is the key in knowing if a connection is parallel in each other or in series with themselves. The current that flows (picture out a current as a flow of water) in a series connection, same current flows on each elements. Similar to a water that flows on a single path. In a parallel connection, different current flows on each element. Similar to a water flow that splits in two or more direction, the water flow will differ from stream to streams with respect to the area, altitude and any other aspects that minimizes the flow of the water, it is also holds true on a parallel connection but is called resistance. 

“If we love our job and what we do. We will never have to work anymore.”-Anonymous

Prelude to Circuits 1 (Ohm's Law, KVL/KCL)

Welcome sir to our first and not so good blog.
We’ve just been studying electrical circuits for about one week, but we have learned so much in just this few days.
Let us start with the meaning of “Electrical Circuit” and its basic units that will be used mostly throughout this semester, if what we believed is true.
For the head start, “Electric circuit” is the interconnection of “circuit elements” which is the basic building blocks of a circuit. This includes the resistors, power source, the electrical/connecting wires and many more and is divided into three types, the “active” which is capable of generating energy, “passive” which absorbs energy, and the “V and I sources” that is the most important active element.

For its basic units, first we have the “Charge”, on other language charge is something used as alternative for paying. Like we are charged 1000 php for purchasing a video game. But in electrical circuits, charge is used differently. Charge in such is defined as the basic quantity of an electric circuits. This means that whatever we measure in our electric circuit, there will always be the presence of charge. And we realized that this “charge” is at most important especially for the likes of us.

Second is the “Current”, current is “charge” flow rate, and is measured in amperes. We have learned that current is what makes the computer that I am using now work, of course with the help of “Voltage”, the charge rate of doing work and is the third basic unit of circuits that we learned. Also there is this “Power” that is defined by the time rate of doing work along with the “Energy” that is the capacity to do work.

“Sources”, we also have discussed the two types of power sources, the “Independent source” which obviously is independent on other elements to perform and supply power. “Dependent source” that depends on other elements to supply its glorious power.

We also have noticed, that this subject, electrical circuits 1, is connected still to our previous subject specifically the differential and integral calculus and geometries. To be able to make and create our own formula to calculate precisely the behavior of a certain charge or unit.

From that we had to jump to the second chapter of electrical circuits, which covers the basic laws used in electric boards and circuits. These two laws was introduced in one of our subject before, we’ve never been so glad to see such familiar words and equations.

Without such further delay, the first law of circuits is the “Ohms law” which states that the “voltage” is directly proportional to the “current” where “resistance” is the constant of proportionality. In short V=IR, but this law can only be use in linear resistors.

Before we continue to the second law, we first discussed about how the elements of circuits can be interconnected. We have been introduced to three new terms which are the “Branch”, which represents a single element, “Node”, the meeting point between two or more branches, and “Loop”, which is any closed path in a circuit.

And so, the second basic law is the “Kirchhoff’s Law”, which is also divided into two parts, the “Kirchhoff’s Current Law” which is the algebraic sum of all entering/leaving current through a node and the “Kirchhoff’s Voltage Law” which states that in any closed loop network, the total voltage around the loop is equal to the sum of all the voltage drops within the same loop.

Learning:

Learning the basics of everything is the key to a brighter future. One will never be able to do algebra, geometry and even calculus without knowing simply how to add, subtract, divide and multiply. In a similar fashion, we will never be able to move forward without know the basics of circuits. 

Ohm's Law, which is the most basic formula that we will have to use mostly in this program, states that voltage is directly proportional to the current of course with the resistance as its constant of proportionality. This means that if the voltage increases, the current will also increase in a similar way.
Second is the Kirchhoff's voltage and current law, Kirchhoff's voltage law states that in a close loop or path, the summation of all the voltages is and must be equal to zero. And Kirchhoff's current law states that in a node, the summation of all the current entering such node, is equal to the summation of all the current leaving the node.

Upon knowing the laws, we had a board work that teaches us how to properly use this laws and we learned how important it is specially for us. Gawd! Being an Electronics and Communication Engineering student is hard.