Relevant Theory/Background Information (Heading, Level 2)
Experiment 2 :
Diodes are basic semiconductor devices that will only allow current to flow through them in one direction only, Forward bias. Diodes are made from two differently doped layers of semiconductor material that form a PN junction. When the diode is reverse biased, the positive holes are attracted towards the negative voltage and away from the junction. Likewise the negative electrons are attracted away from the junction towards the positive voltage applied to the cathode. As higher voltages are applied in reverse polarity to the diode, the depletion layer becomes wider as the applied voltage is attracting more charge carriers away from it. The diode will not conduct with a reverse voltage when a reverse bias applied. Once the voltage is applied in the forward direction, current will flow; in this case as the voltage is increased more current flows.
Experiment 2:
Rectifiers convert an AC into a DC by allowing a current to flow through it in one direction only. There are two kinds of rectifiers,
Half- wave: A half-wave rectifier allows only one half-cycle of the AC voltage waveform to be applied to the load, using one half cycle of the applied voltage, the other half cycle being suppressed because it conducts only in one
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The Zener Diode was used in its reverse bias. Zener Diode was basically used to produce a stabilized voltage output with low ripple under varying load current. The load current observed ranged btween 0 mA and 10 mA. By passing a small current through the diode, close to 0 A, from a voltage source, the zener diode conducts sufficient current to maintain a voltage drop at Vout. The zener diode as a voltage regulator, the clipping circuits are used to remove the part of a signal that undefined; while, the clamping circuits are used to shift an input signal by an amount defined by an independent voltage
Power Supply- The power supply which is also known as the PSU is the component the supplies power from the mains electric into the PC. The PSU converts mains AC to low-voltage regulated DC power for the internal components of a computer
The refrigeration cycle is composed of 5 main components which will be explained in this essay. There are many different factors that allows refrigeration to work. We’ll also go over the basic principles of refrigeration, how the refrigeration cycle works, and types of heat transfer.
Different refrigeration cycles exist including the gas cycle, the vapour-absorption cycle, and the vapour-compression cycle. The gas cycle uses a refrigerant, often air, which does not change state, but instead remains as a gas throughout the entire cycle. The vapour-absorption cycle, which preceded the vapour-compression cycle, is a heat operated cycle. It requires little electricity, but a lot of heat energy, and is usually only used where waste heat is plentiful (Ameen, 2006). The vapour-compression cycle is favoured over all others in both domestic and industrial installations as it is the most efficient system available. It works by pumping a refrigerant, which chang...
A battery is a device which converts chemical energy into electrical energy. A battery usually consists of two or more cells connected in series or parallel, you can also have a single cell battery. All cells consist of a positive electrode, and a negative electrode. An electrolyte is a liquid substance capable of conducting electricity. In this substance one of the electrodes will react producing electrons, while the other will except electrons. When the electrodes are connected to a device to be powered, called a load, an electrical current flows.
When introduced into an ionic solution, positively charged ions will be electrostatically attracted to the anode and the negatively charged ions will be electrostatically attracted to the cathode. This act of moving ions means that charges are able to move from anode to the cathode and complete the circuit. These moving ions are essentially the same as moving electrons (electricity). This process of putting electrodes into a solution, using a direct electric current (D.C.), and separating chemicals based on their charge is known as electrolysis
To understand how this electricity works we must start with the basics. The atom is the smallest unit of matter, consisting of protons, neutrons, and electrons. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge. Electric charges that are the same repel each other and charges that are different attract each other. Electric charges can exist alone, unlike magnetic poles.
There are generally two types of single-phase double-wound transformer constructions, the core type and the shell type. Core has a small cross section of iron; more number of turns is mandatory because the high flux may not reach the core. Core type is used for high-voltage service, since it has adequate room for insulation. Shell-type transformer has double magnetic circuit and three branches. Both windings are placed on the central branch. The coils reside in the entire space of windows.
A capacitor is a device for electrical charge. A simple capacitor is two plates made of an electrically conducting material separated by a non-conducting material or dielectric. A capacitor can come in a huge variety of sizes and types for use in regulating power as well as for conditioning, smoothing and isolating signals. Almost every electrical and electronic system uses them. [1]
AC and DC literally stand for Alternating Current and Direct Current. Direct Current is very convenient and is used in many modern day utilities. For a circuit with DC the current is constanly in one direction, while the voltage remains constant. This makes for a simplistic circuit, for example a flashlight, The batteries are a source of electrochemical DC power and . However AC is called Alternating Current because the voltage changes from negative to positive a given number of times a second, this is also described as the frequency of the power. An example of this would be a motor ran by a hand crank. The inversing of charges creates a sinusoidal graph which looks something like figure 1 (given in radians). This makes for an unsteady power source and can often times be warped from the sinusoidal shape. So the main difference between AC and DC is the way the energy is transmitted.
On the other hand, chemical reactions in a rechargeable battery are reversible – meaning that the products produced in the chemical reactions to produce electricity can go back to their original state by using an outside electric power source [4].
All useful generators of electricity come in two basic forms, alternating current and direct current. Direct current (dc) comes from generators that do not change in polarity, always producing a positive charge. In alternating current (ac) the polarity of the terminals is always changing from positive to negative. Thus you are left with alternating current flow. There are different ways of measuring and generating alternating and direct current.
This produces a positive charge at bottom surface with an equal amount of negative charge at upper surface. So in p-type semiconductor, the bottom surface is positively charged and the upper surface is negatively charged.
In thermodynamics Refrigeration is the major application area, in which the heat is transferred from a lower temperature region to a higher temperature region. The devices which produce refrigeration are known as Refrigerators and the cycle on which it operates are called refrigeration cycles. Vapour compression refrigeration cycle is the most regularly used refrigeration cycle in which the refrigerant is alternately vaporized and condensed and in the vapor phase it is compressed. Gas refrigeration cycle is the well-known refrigeration cycle in which cycle refrigerant remains in the gaseous phase throughout the cycle. Cascade refrigeration are the other refrigeration cycles discussed in this chapter; absorption refrigeration is the one more refrigeration cycle which is used where the refrigerant is dissolved in liquid before it is compressed. One more refrigeration in which refrigeration is produced by passing the electric current through two dissimilar materials is called as the thermoelectric refrigeration.
...ed if the current was alternating ( Bushong, 2008). Transformers are necessary to supply a high voltage to the