1. transformation of AC to Dc voltages is unbounded.

1. Identify the types of diodes. a.   Small Signal DiodeThis is a small device with disproportional characteristics and whose applications involved high frequency and very low currents namely radios and television. The small signal diode could be silicon or germanium doped diode. Ther cathode is marked with black or red. The diode is also called as Glass Passivated Diode because it is enveloped with a glass.b. Large Signal DiodeThis type of diode usually has large PN junction; in this case, the transformation of AC to Dc voltages is unbounded. The main applications of these diodes are in battery charging devices. This can be used to suppress high peak voltages since it has a high current and voltage performance.c. Zener DiodeIt works under the principle of Zener breakdown. This type of diode is quite similar to normal diode in forward direction. This is designed to prevent the other semiconductor devices from momentary voltage pulses which acts as a voltage regulator.d. Light Emitting Diode (LED)LEDs  convert  electrical  energy  into  lightenergy in which it undergoes electroluminescence process. In this process, electrons and holes are recombined to produce energy in the form of light. Most applications of these diodes are flashes, and light signals.e. Constant Current DiodeThis type of diode is also known as current-regulating or constant current diode orcurrent-limiting, or diode-connected transistor. Mainly, its focus is to regulate the voltage at a particular current. f. Schottky DiodeThis type of diode is made by contacting the semiconductor material with metal. The forward voltage drop is decreased to minimum. This diode is mainly used in switching applications. g. Shockley DiodeA type of diode which has four layers, which is also called as PNPN diode. This diode is the same as a thyristor without a gate terminal. As there is no trigger, you can only conduct the diode by providing forward voltage. It stays on one’s it is turned on, and off if it’s turned off.h. Step Recovery DiodeThe diode is also called as snap-off diode or charge-storage diode. This type of diode stores charge from positive pule and uses in the negative pulse of the sinusoidal signals. Mostly, these diodes are used in higher order multipliers and in pulse shaper circuits. i. Tunnel DiodeTunnel Diodes are used as high-speed switch. These types of diodes are normally used in microwave oscillators and amplifiers, which acts as most negative conductance device.j. Varactor DiodeThese diodes are also known as Varicap diodes. This diode acts like a variable capacitor. These are commonly used as voltage controlled oscillator for cell phones, satellite pre-filters and many more. k. Laser DiodeLaser diodes are commonly used in fiber optic communication, barcode readers, laser pointers, CD/DVD/Blu-ray reading and recording, and laser printing.l. Transient Voltage Suppression DiodeThe operation of this diode is similar to Zener diode operation. These diodes are having applications in the telecommunication fields, medical, microprocessors and signal processing. m. Gold Doped DiodesThe type of diode allows the diode to operate in signal frequencies. o. Peltier DiodeA Peltier device is a heat engine working backwards as a refrigerator.2. Discuss, illustrate and derive the related equation of various rectifier circuits.Half wave RectifierA diode conducts if it is forward biased or, conducts only in one direction. A rectifier is a device that converts alternating current to direct current which flows only in one direction. For a half wave rectifier circuit, only half of the cycle o9f the AC voltage is to be applied in the load. The circuit comprised of a semiconductor diode and a load resistance. The ac voltage changes polarities after every half cycle of the input wave. During the positive half cycle, the diode is forward biased and conducts current. However, during the negative half cycle of the input ac voltage, the diode is reversed biased which does not conduct current. Thus, the current and voltage that can be measured across the load is zero. Thus, forming the output waveform shown below. n. Super Barrier DiodeThis is a type of rectifier diode that have a low forward voltage drop as Schottky diode with surge handling capability. Average Value of the Half – Wave Output Voltage= = 0.318 Effect of the Barrier Potential on the Half – Wave Rectifier Output (   ) = (   ) ? 0.7Peak Inverse Voltage (PIV)=   (   )Full Wave RectifierRectfification is the process of converting AC current into DC current. However, rectiofication can be achieved through single or group of diodes. A full wave rectifier is a type of circuit which converts both half cycles of the AC signal into pulsating DC signal. However, there are two types of full wave rectifier-center tapped and full wave rectifier.2  =Center Tapped TransformerA center tapped transformer is formed whenan additional wire is connected across the exact middle of the secondary winding of a transformer. In this transformer, it works similarto a normal transformer. The input voltage is coupled through the transformer to the center – tapped secondary. For a positive half cycle of the input voltage, the polarities of the secondary voltages.Effect of the Turns Ratio on the Output Voltage= ? 0.7 2 Peak Inverse Voltage= 2   (   ) + 0.7Bridge Full – Wave RectifierA bridge rectifier uses four diodes connected as shown below.The picture shown above is the flow of current during the positive half cycle.The figure above shows the negative half cycle. In this case, the other two diodes are reverse-biased.Bridge Output Voltage (   ) = (sec )DC Level= 0.636 Bridge Output Voltage (   ) = (sec ) ? 1.4Peak Inverse Voltage= (   )= (   ) + 0.73. Discuss the block diagram of a power supply. You may illustrate it and the corresponding waveforms.Block diagram of a power supplyIn a basic power supply the input power transformer has its primary winding connected to the mains (line)supply. Secondary winding, which is electromagnetically coupled but electrically isolated from the primary. This is used to drive the circuit of the power supply.For the next process, rectification is used to convert AC to DC. Sometimes, the method of rectification is referred to by counting the number of DC “pulse” output for every 360 degrees of electrical rotation.After it, is the rectifier stage. In this stage, it converts AC to DC which flows in one direction. There are three types of rectifier circuits namely half wave, full wave, and bridge rectification. For the half wave rectification, it only conducts on one half cycle of the AC input. As the amplitude of the half cycle for which the diode conducts, it will be reduced by approximately 0.7 V due to the voltage drop across the silicon diode. For full wave rectification, it uses two silicon diodes, each of these outputs is half waved rectified, producing two pulses of current every cycle. The output frequency, therefore, produces twice the input frequency. Lastly, the bridge rectifier, uses four diodes arranged in a bridge circuit.In power supplies, capacitors are placed to filter the pulsating DC output after rectification. In this way, nearly constant DC voltage is supplied in the load connected.The regulator provides a stable DC voltage regardless of the load. This maintains a constant voltage level. 4. State other applications of a diode• Rectificationo An  electrical  device  thatconverts alternating current to direct current which flows in only one direction.• Clampo It is also known as dc restorer.• Clippers/Limiterso A diode clipping circuit can be used to limit the voltage swing of a signal.• Doublero A DC restorer followed by a peak detector.• Diode Logico It can be used as a basic logic OR gate.• Standby Voltage• Gate• Reverse Current Protectiono This circuits is to avoid the damage that occurs due to connecting the battery I a wrong way or reversing the polarities of the DC supply.• Voltage Spike Suppressiono Sudden removal of supply source produces a higher voltage due to its stored magnetic field energy.• Solar Panelso These are used for protection of solar panels which are called bypass diodes.