If you are in class 11th conceptually, you have to face a problem in class 12th. You will find the class 12th syllabus more accessible as compared to class 11th.
Average students would be able to score 60 out of 80, say experts. An average student will not be able to score more than 60 marks out of Most of the students finds the Class 12 Physics subject difficult. Pooja Roy is a Senior Content Developer and also handles Edufever School with a mission to make education accessible to all. Save my name, email, and website in this browser for the next time I comment. Notify me via e-mail if anyone answers my comment. Which study material is best for class 12th?
Is Edufever study material free? Does Edufever provide study material? What is the 12th class called in India? Which board is best for class 12? CBSE board is better for pursuing class 12th. How can I make a 12th study plan? Which is tough, 11th or 12th? Before the circuit connection it should be check out working condition of all the Component. Result: 9. Power Electronics Lab Manual 9 Viva-voce: 1. Define holding current,latching current, ON state resistance,break down voltage.
Write an expression for anode current? Mention the applications of S. Power Electronics Lab Manual 11 Fig. Apparatus Required: Table 4 S. Name of the equipment Range Qty Theory: A metal oxide semiconductor field effect transistor is a recent device developed by combining the areas of field effect concept and technology.
It has three terminals called drain, source and gate. The control signal or gate current less than a BJT. The device is in OFF state upto some voltage called threshold device voltage.
Procedure: Transfer Characteristics: 1. Switch on the regulated power supply. Keep VDS constant say 10V. Tabulate the readings in the table. Make the connections as shown in the circuit diagram. Initially set VGS to some value say 10V. At particular value of VGS there a pinch off voltage between drain and source. Precautions: 1. Care should be taken such that the values of the components of the circuit does not exceed to their ratings maximum value.
Before the circuit connection , check out the working condition of all the components. Result: Viva-voce: 1. Power Electronics Lab Manual 15 Apparatus Required: Table 7 S. IGBT is also known as metal oxide insulated gate transistor. It was also called as insulated gate transistor. The static characteristics or output characteristics of IGBT shows plot of collector current IC vs collector —emitter voltage VCE for various values of gate emitter voltage.
In the forward direction the shape of output characteristics is similar to that of BJT and have the controlling parameter is gate-emitter voltage VGE because IGBT is a voltage controlled device. The device developed by combining the areas of field effect concept and technology.
Power Electronics Lab Manual 19 2. Set VCE to some say 10V. Slowly vary gate emitter voltage VGE by varying V1. Tabular Column: Table No. Result: Viva Voce: 1. Power Electronics Lab Manual 21 2.
What are merits of IGBT? What are demerits of IGBT? How is IGBT turned off? What is threshold voltage? On the positive half-cycle of SCR anode voltage the capacitor charges to the trigger point of the SCR in a time determined by the RC time constant and the rising anode voltage. The top plate of the capacitor charges to the peak of the negative voltage cycle through diode D2 on the negative half-cycle, resetting it for the next charging cycle.
Procedure: 1. Give the AC power supply from the source. Power Electronics Lab Manual 25 3. Observe various voltage waveforms across load, SCR and other points, by varying the load resistance. Compare practical obtained voltage waveform swith theoretical waveforms and observe the firing angle in R-C Triggering.
Waveforms: a b Fig. What is the maximum firing angle of RC-triggering and why? What are the limitations of RC triggering circuit? Apparatus Required: Table 2 S. The circuit diagram of an R Triggering consistsof Simple resistor; diode combinations trigger and control SCRs over the full electrical degree ranges, performing well at commercial temperatures. These types of circuits operate most satisfactorily when SCRs have fairly strong gate sensitivities.
Since in a scheme of this type a resistor must supply all of the gate drive required to turn on the SCR, the less sensitive the gate, the lower the resistance must be, and the greater the power rating. Diode D1 blocks reverse gate voltage on the negative half-cycle of anode supply voltage.
It is necessary to rate blocking to at least the peak value of the AC supply voltage and the trigger voltage producing the gate current to fire IGF are in phase. Power Electronics Lab Manual 29 2. Connect the AC power supply from the source indicated in the front panel. Connect Load i. Observe various voltage waveforms across load, SCR and other points. Waveforms: a b c Fig. Compare practical obtained voltage waveforms with theoretical waveforms and observe the firing angle in Resistance Triggering.
Viva Voce: 1. What is the maximum firing angle of R-triggering circuit and why? What are the disadvantages of R triggering? Mention different methods of trigerring SCR? Power Electronics Lab Manual 31 4. Why gate triggering is preferred? Remarks Signature of the facult Circuit Diagram: Fig.
Apparatus Required: Table 3 S. The emitter potential V is varied depending on the charging rate of capacitance C. The charging resistance Rc should be such that the load line intersects the device only in the negative resistance region.
It is defined as UJT is a highly efficient switch. The rise time output pulse will depend on the switching speed of the UJT and duration will be proportional to the time constant RB1C of the discharge circuit. Power Electronics Lab Manual 33 Observe the waveforms across the load and SCR and other points, by varying the variable resistor Rc and resistance load, observe firing angle of SCR.
Use differential module for observing two waveforms input and output simultaneously in channel 1 and channel 2. For Relaxation Oscillator: 1. We get equidistance pulses at the output of pulse transformer. The frequency of pulse can be varied by varying the potentiometer. Observe that capacitor charging and discharging time periods and calculate frequency and RC time constant of UJT Relaxation Oscillator by using given formulas Precautions: 1.
Before the circuit connection it should be check out working condition of all the Power Electronics Lab Manual 35 Component. Why is the isolation needed between Thyristor and firing circuit? What are the applications of UJT trigger circuits?
Name of the equipment Range Qty Theory: Commutation is the process of turning off the SCR and it normally causes the transfer of current flow to other parts of circuit. The device is automatically turns off due to the natural behavior of the source voltage. This is known as natural commutation or line commutation.
This technique is called forced commutation and normally applied in DC to DC converters. Forced Commutation circuits can be classified as i. Class-A Commutation Series resonant commutation circuit ii. Class-B Commutation Parallel resonant commutation circuit iii. Class-C Commutation Complementary commutation circuit iv.
Class-D Commutation Auxiliary Commutation v. Connect the circuit as shown in the circuit. Switch on the DC supply to the power circuit and observe the voltage waveform across load. Repeat the same for different values of L,C and R. Class-B Commutation: 1. Class-C Commutation: 1. Observe the waveforms across R1,R2 and C by varying frequency and also duty cycle potentiometer.
Repeat the same for different values of C and R. Class-D Commutation: 1. Power Electronics Lab Manual 41 3. Now switch ON the trigger output and observe the voltage waveform across the load, T1, T2 and capacitor. Note down the voltage waveforms at different frequency of chopping and also at different duty cycles.
Repeat the experiment for different values of load Resistance, commutation inductance and capacitance. Connect the trigger output T1 from the firing circuit to the SCR. Connect T2 to the Transistor base and emitter points. Switch on the trigger output and observe and note down waveforms. Repeat the Same by varying frequency and duty cycle. Power Electronics Lab Manual 43 Component.
Class-E Commutation What is meant by commutation? What are the different types of commutation techniques? What is meant by impulse commutation? Power Electronics Lab Manual 45 4. What is meant by external pulse commutation? When the circuit is said to be under damped circuit? In which type of converter forced commutation is employed? Remarks Signature of the faculty Circuit Diagram: Fig. Name of the equipment Range Qty Power Electronics Lab Manual 47 Theory: The circuit arrangement of a 1-ph converter is shown in figure 1.
In the positive half cycle thyristor T1 is forward biased. DM conducts to provide continuously current in case of inductive loads. Load is connected to supply through T2 and D1.
The converter has a better power factor due to the freewheeling diode and is commonly used in applications up to 15KW where one quadrant operation is acceptable.
The half controlled bridge has the inherent freewheeling action and analysis is more or less the same with or without a freewheeling diode is connected across the load. Make all connections as per the circuit diagram 2. Connect firing pulses from firing circuit to Thyristors as indication in circuit 4. By varying firing angle gradually up to and observe related waveforms 7. For RL Load connect a large inductance load in series with Resistance and observe all waveforms and readings as same as above.
Observe the various waveforms at different points in circuit by varying the Resistive Load and Inductive Load. Calculate the output voltage and current by theoretically and compare with it practically obtained values. Precautions: Power Electronics Lab Manual 49 1. Use only isolated power sources either isolated power supplies or AC power through isolation power transformers. This helps using a grounded oscilloscope and reduces the possibility of risk of completing a circuit through your body or destroying the test equipment.
Waveforms: What is meant by half controlled rectifier? What is the effect of adding free wheeling diode? Give at least five application of phase controlled rectifier? What is meant by firing angle?
What is other name for single half controlled rectifier? What is meant by pulse number? Remarks Signature of the faculty Circuit Diagram: The load is assumed to be R and RL.
Dm conducts to provide the conductivity of current in the inductive load. During the negative half cycle of the input voltage thyristors T2 and TI 2 are forward biased. Make all connections as per the circuit diagram Power Electronics Lab Manual 55 2.
Tabulate all readings for various firing angles. What is a full controlled rectifier? How can we control the output voltage of a single-phase full converter? What is the type of commutation used in a single phase full controlled converter? What is rectification mode and inversion mode? What are the applications of Single phase fully controlled rectifiers?
Remarks Signature of the faculty Voltage Controller with R load Fig. Date: ………… Voltage Controller Aim: To observe the output wave forms of 1-phase A. The circuit diagram of Single phase AC voltage controller is shown in figure. The input and output voltage waveforms are also shown. During the other half cycle of input voltage waveform SCR T2 conducts. Power Electronics Lab Manual 61 1.
IRS switch and trigger output ON switch 5. Observe waveforms in CRO, across load by varying firing angle gradually up to Calculate the output voltage and current by theoretically and compare with it practically obtained values Waveforms: i For R-Load Power Electronics Lab Manual 63 1.
What is ac voltage controller? What are the applications of ac voltage controllers? What are the two types of control? What are the merits and demerits of voltage controllers? Why is the trigger source for the two Thyristor isolated from each other in a single-phase Power Electronics Lab Manual 65 voltage controller?
What is the difference between cycloconverters and ac voltage controllers? Remarks Signature of the faculty Circuit Diagrams: Power Electronics Lab Manual 67 Fig. Out of them T1, T2 are responsible for generating positive halves forming the positive group. The other two T3, T4 are responsible for negative haves forming negative group. Questions based on the most recent universal rules have been added in the Physical education practical book for class 12 pdf links which you will find in the above section.
Experiments are an integral part of understanding the fundamentals of physical education. Learning through experiments is an essential aspect of all physical education courses because the experience is acquired through experimentation.
The ultimate goal of these PDF links for the Class 12 Physical Education practical book is to provide students with a thorough understanding of the subject, including all applicable concepts and skills.
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