Then, Capacitors in Parallel have a common voltage supply across them. Then, Capacitors in Series all have the same current so each capacitor stores the same amount of charge regardless of its capacitance. Capacitors connected together in series all have the same amount of charge. The direction of this magnetic field can be thought in terms of a wood screw being screwed into the conductor in the direction of the flow of current, with the head of the wood screw being rotated in the direction of the lines of force.
If we now take this length of wire and form it into a coil of N turns, the magnetic flux surrounding the coil is increased many times over for a given coil of wire compared with the flux produced by a single straight length.
Also, if the current which is flowing through the coils conductor is increased in magnitude, the magnetic flux produced around the coil will also increase in value. However, as the strength of the magnetic flux increases, it induces a secondary An Inductor is a coil of voltage within the coil called a back emf electro-motive force.
Then for a coil of wire which opposes the wire, a self-induced voltage is developed across the coil due to the change in flow of current through current flowing through the coil. The polarity of this self-induced voltage produces itself in the form of a a secondary current in the coil that generates another magnetic flux which magnetic field opposes any changes to the original flux.
In other words, the instant the main current begins to increase or decrease in value, there will be an opposing effect trying to limit this change. But because the coil of wire is extremely long, the current through the coil cannot change instantaneously it takes a while for the current to change due mainly to the resistance of the wire and the self-induced effects of the wire coil.
The ability of a coil to oppose any change in current is a result of the self-inductance, L of the coil. This self- inductance, simply called inductance, value of an inductor is measured in Henries, H. Then the greater the inductance value of the coil, the slower is the rate of change of current for a given source voltage.
Then Inductance is the characteristic of an electrical conductor that opposes a change in current flow. An inductor is a device that stores energy within itself in the form of a magnetic field. This results in a much stronger magnetic field than one that would be produced by a simple coil of wire.
Inductors can also be fixed or variable. Inductors are mainly designed to introduce specific amounts of inductance into a circuit. They are formed with wire tightly wrapped around a solid central core which can be either a straight cylindrical rod or a continuous loop or ring to concentrate their magnetic flux. The inductance of a coil varies directly with the magnetic properties of the central core.
Ferrite and powdered iron materials are mainly used for the core to increase the inductance by increasing the flux linking the coil.
Increasing levels of inductance can be obtained by connecting the inductors in series, while decreasing levels can be obtained by connecting inductors in parallel.
However, there are certain rules for connecting inductors in series or parallel and these are based on the fact that no mutual inductance or magnetic coupling exists between the individual inductors. In the Resistors in Series tutorial we saw that the different values of the resistances connected together in series just "add" together and this is also true of inductance.
Inductors in series are simply "added together" because the number of coil turns is effectively increased, with the total circuit inductance LT being equal to the sum of all the individual inductances added together. The voltage drop across all of the inductors in parallel will be the same. If the voltage across a resistor varies sinusoidally with respect to time, as it does in an AC circuit, the current flowing through the resistor will also vary.
In an AC resistance, the current and voltage are both "in-phase" as there is no phase difference between them. A circuit consisting of reactance inductive or capacitive resistance and a resistance will have an equivalent AC resistance known as Impedance, Z. Impedance is the phasor sum of the circuit's reactance, X and the resistance, R. Note that although impedance represents the ratio of two phasors, it is not a phasor itself, because it does not correspond to a sinusoidal varying quantity.
Impedance, which is given the letter Z, in a pure ohmic resistance is a complex number consisting only of a real part being the actual AC resistance value, R and a zero imaginary part, j0. Because of this Ohm's Law can be used in circuits containing an AC resistance to calculate these voltages and currents. As a pure resistor has no reactance, resistance is, for all practical purposes, unaffected by the frequency of the applied sinusoidal voltage or current.
In such circuits we can use both Ohms Law and Kirchoff's laws as well as simple circuit rules for calculating the voltage, current, impedance and power as we would in DC circuit analysis. When working with such rules it is usual to use rms values only. Capacitors oppose these changes in sinusoidal voltage with the flow of electrons through the capacitor being directly proportional to the rate of voltage change across its plates as the capacitor charges and discharges.
Unlike a resistor were the opposition to current flow is its actual resistance, the opposition to current flow in a capacitor is called Reactance. Like resistance, reactance is measured in Ohm's but is given the symbol "X" to distinguish it from a purely resistive ohmic R value and as the component in question is a capacitor, the reactance of a capacitor is called Capacitive Reactance, XC which is also measured in Ohms. In a pure AC Capacitance circuit, the voltage and current are both "out-of-phase" with the current leading the o o o 5.
The effect of a sinusoidal supply produces a phase difference between the voltage and the current waveforms. In an AC circuit, the opposition to current flow through an inductors coil windings not only depends upon the inductance of the coil but also the frequency of the AC waveform.
The opposition to current flowing through a coil in an AC circuit is determined by the AC resistance, more commonly known as Impedance Z , of the circuit. As the component we are interested in is an inductor, the reactance of an For more information visit our website at: www. In other words, an inductors electrical resistance when used in an AC circuit is called Inductive Reactance. Inductive Reactance which is given the symbol XL, and is the property in an AC circuit which opposes the change in the current.
In other words they "filter-out" unwanted signals. Filters are "attenuating" the rest. Then a band pass filter has two corner or cut- off frequencies. The band stop filter blocks rejects or severely attenuates a certain band of frequencies between its two corner frequencies while allowing all those outside of this stop-band to pass.
They neither are not good conductors nor are they good insulators hence their name "semi"-conductors. They have very few "fee electrons" in their valence shell because their atoms are closely grouped together in a tight crystalline pattern called a "crystal lattice". However, their ability to conduct electricity can be greatly improved by adding certain "impurities" to this crystalline structure thereby, producing more free electrons than holes or vice versa. By controlling the amount of impurities added to the semiconductor material it is possible to control its conductivity.
These impurities are called donors or acceptors depending on whether they produce electrons or holes respectively. This process of adding impurity atoms to semiconductor atoms the order of 1 impurity atom per 10 million or more atoms of the semiconductor is called Doping. Silicon Atom Structure In order for a silicon crystal to conduct electricity, we need to introduce an impurity atom that has five outer electrons in its Co-valent Bonds 4 electrons outermost valence shell to share with its neighbouring atoms.
The Si in valence most common type of "pentavalent" 5-electron impurities used to shell dope silicon are Antimony symbol Sb or Phosphorus symbol P , because they have 51 electrons arranged in five shells around their nucleus with the outermost orbital having five electrons. Si Si Si The resulting semiconductor basics material has an excess of current- carrying electrons, each with a negative charge, and is therefore Shared referred to as an "N-type" material. In these types of materials the donors are positively charged and there are a large number of free electrons.
If we go the other way, and introduce a "trivalent" 3-electron impurity into the crystalline structure, such as Boron symbol B or Indium symbol In , which have only three valence electrons available in their outermost orbital, the fourth closed bond cannot be formed.
Therefore, a complete connection is not possible, giving the semiconductor material an abundance of positively charged carriers known as "holes" in the structure of the crystal where Semiconductor materials electrons are effectively missing.
Then P-type types of integrated circuits Semiconductors are a material which have trivalent impurity atoms Acceptors added and conducts by the movement of "holes". In these types of materials the acceptors are negatively charged and there are a large number of holes for free electrons to fill. So by using different doping agents to a base material of either Silicon S or Germanium Ge , it is possible to produce different types of basic semiconductor materials, either N-type or P-type for use in electronic semiconductor components, microprocessor and solar cell applications.
The semiconductor diode is a device that allows current to pass through it in only one direction. This characteristic of a diode has many useful applications in electronics such as rectification of AC voltages and currents to DC. However, unlike a resistor, a diode does not behave linearly with respect to the applied voltage as the diode has an exponential I-V relationship and therefore we can not described its operation by simply using an equation such as Ohm's law.
However, when the anode is made more negative than the cathode, the diode is classed as being "reversed biased" and blocks the flow of current up to its reverse breakdown voltage at which point the diode looses control. Note that the arrow points in the direction of conventional current flow and the diodes two connections are known as the Anode, A and Cathode, K. The cathode negative end is often marked with a band for identification. Semiconductor diodes are formed using either Silicon or Germanium semiconductor materials.
Diodes are classed as either small signal diodes for use in a variety of small voltage applications or classed as power diodes for use in rectifying and mains powered circuits. Germanium diodes, unlike silicon diodes, only require a forward-biasing voltage of 0. Diodes being one way devices cannot be connected together in series randomly. Only circuit, "A" will conduct current. A full-wave rectifier circuit reduces the ripple by a factor of two.
Also the output DC ripple is twice the input supply frequency. However, if we increase the reverse voltage across the diode sufficiently high enough, the diode's PN-junction will breakdown and the diode will become damaged allowing current to flow.
The reverse voltage level at which this breakdown occurs is called the breakdown voltage, or peak reverse voltage.
A zener diode is a special type of diode that conducts normally in the The zener diode is a special forward-biased mode but is designed to operate in the reverse-biased type of diode designed to mode so that at a certain breakdown voltage point, the reverse voltage operate in the reverse bias causes the diode to conduct in a controlled way allowing a reverse direction and is used to current to flow through a series limiting resistor, Rz.
This breakdown stabilize or regulate a voltage voltage is called the zener voltage, Vz. The breakdown voltage point of a zener diode, Vz is determined by the resistivity of the diodes junction which is controlled by the doping technique used during its manufacture with zener breakdown voltages ranging from 2. The voltage across the zener diode, Vz, remains reasonably constant over a wide range of reverse currents passing through the zener diode. This ability to control itself can be used to great effect to regulate or stabilise a voltage source against supply or load variations.
In electronic circuits, transistors have two basic functions: "switching" Transistors are electronic digital electronics or "amplification" analogue electronics. Basic Electronics Engineering Study Materials. You can also download or view the entire notes for the subject. Click on View or Download to access the notes. The notes published below is as per to the syllabus given by the Amity University. In this post you will find the solved question paper for the subject Data Structures Using C.
Data Structures is one of the important s To prove that like charges repel, you have to repeat Steps 1 through 4. And then follow the steps below; Step 5. Tie each balloon with a string, then tie their strings together as demonstrated in the image provided.
Step 6. Hold the balloons in front of you while making sure that they're not touching any surface. Now, assuming you did not pump the balloons with helium, the balloons should be hanging down towards the floor.
Well, here's the explanation for that. Remember, that the balloons after going through steps became negatively charged. Well, now what you've got in your hand are two balloons that are both negative, that is why they are avoiding each other like a plague. Because remember the other rule? Like charges repel. Now go on your merry way and have a soda can race with that balloon. To identify whether a certain point is negative or positive, you must have a reference point for it.
Going back to our previous lecture, when we call something positively charged, it means there are more protons. Another true statement would be, that it is positively charged because it has more protons and less electrons. Well, we want to focus on the fact that it has less electrons, as the reason for its positive polarity.
An accurate definition would be that an object or a point in an object can be considered positive if it has less electrons than another object or point in an object. Correspondingly, an object or a point in an object can be considered negative if it has more electrons that the other object or point in an object. To understand this better, look at the image provided in this lecture.
In the image, what point do you think is positive? What point do you think is negative? If you answered Point A for the first question, then you are correct! If you answered Point B for the second question, then you are correct again!
Here are the important points; 1. When an object has more electrons than another object, it is negative. When an object has less electrons than another object, it is positive.
Electrical energy is produced when there is a change in the electrical balance of atoms. That is to take neutrally charged atoms and add or take away its electrons in order to render it unbalanced or no longer neutrally charged. There are many ways to create this electrical imbalance in order to produce electricity; 1. Magnetism - an example would be magnet motors. Chemical - an example would be batteries. Light - an example would solar cells. Friction - an example would be seismic energy dissipation devices.
There, so if you were wondering how electricity is produced, it is through manipulation of electrons and inducing an electrical imbalance in atoms.
Okay, so far so good, we're almost done with Chapter One, hazaaaa! So far we've covered additional topics; 1. Basic Law of Electrical Charges 2. Experiment 3. Polarity and Reference Points 4.
Sources of Electrical Energy Important things to remember; 1. Opposites Attract, Likes Repel 2. You can do that experiment too 3. Negative has more electrons in comparison to 4. Positive has less electrons in comparison to 5. Electrical Energy can be produced from inducing an electrical imbalance in atoms.
Another day, another bacon. Opposite charges attract and like charges repel. When two objects of like charges are placed in proximity of each other, how far do they repel each other? When they are of opposite charges, how close do they move towards each other?
What determines how much force of attraction or repulsion is between two charged bodies? Allow me to introduce a friend of mine, Charles Coulomb. My dearest friend Mr. Coulomb found out that the force F of attraction or repulsion between two charged bodies is: directly related to the product of their charges and inversely related to the square of distance between them.
Unit of charge : Q coulomb How many electrons are in 1 coulomb you say? That is 6, , , , , , electrons or 6. Well, when the two charges are higher, the force to which they can attract or repel each other is also higher. That is what is meant by directly proportional. F is higher when Q1 and Q2 is higher. It is because we multiply the two charges, when we multiply things, the result becomes bigger. And notice that in the equation, F is directly across Q1 and Q2? This means that whatever happens to Q1 and Q2, the same exact thing happens to F.
So if Q1 and Q2 goes up, well you guessed it right, F also goes up. Also, when the distance is longer between the two charged objects, the force to which they can attract or repulse each other decreases.
Which is what is meant by inversely proportional. F is decreased when distance is increased. It is because we divide by distance, so of course when we divided something, the result becomes smaller. Notice that in the equation, the distance is below F? This means that when distance changes, the opposite of that change happens to F. So if distance goes up, F goes down. Important points: 1. Any substance or body that has excess electrons is negatively charged.
Any substance or body that has a deficiency of electrons is positively charged. It becomes actual movement only when a path is provided, i. So, when you purchased a brand new battery, the positive is one side of the battery, and the negative is on the other. What makes the positive side of the battery more positive than the other side, is because it has fewer electrons in comparison. Accordingly, what makes the negative side of the battery negative more than the other side, is because it has more electrons in comparison.
Now, when we connect one side of a wire to the positive terminal, and the other side of the wire to the negative terminal, what happens is, we provide a path for the electrons to travel. This movement of electrons will continue until the amount of electrons on each side of the terminals are equal. This is when your battery is considered out of charge.
Want to recharge your battery out in the desert? Let it soak in the sun all day. Okay, now it wont fully recharge, but it will recharge some.
How does this happen you say? Assuming that the casing of your battery is a conductor example: some sort of metal this method should work on most AA, AAA cells and 9V batteries.
The sun supplies the additional electrons to recharge your batteries. But there is no wire from the sun to the battery, so how do the electrons travel to battery? We forget that, although the air is a poor conductor, it is still a conductor.
The air provides the path for electrons to travel from the sun to the battery. Now, that I think about, the space where the sun is has no air. So how do the electrons travel from the sun to earth? Maybe in this case the electrons didn't need air to travel, maybe it just needed space.
Sounds to me like you have some researching to do. How is the sun burning without air? I thought in order to create fire, there has to be air. Ever lit up a candle and covered it entirely with a jar? Doesn't it die afterwards? If space has no air, then where is the sun getting the air to burn? Did it suck all the air out of space in our solar system? Is this why there is no air in outer space?
Voltage - which is measured in volts 2. Current - which is measured in ampere 3. Resistance - which is measured in ohms Now, we have mentioned earlier that: Voltage is the ability of electrons to move based on polarity.
And to be electrically accurate, it is the potential difference between two points the positive and negative terminals. Then what is current? In that voltage is the ability, Current is the actual movement of electrons. In simple terms, voltage is the doer and current is the action.
Current is simply the electron flow. How about resistance? What is resistance? Another important question in the scheme of things is, which way do electrons flow? Electrons flow from negative to positive. In the case of a circuit or battery, that is from the negative side of the terminal to the positive side of the terminal. To understand this better, look at the image provided for this lecture.
So when we say five volts, we can write 5V. You must capitalize.
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