5. Connect CRO and observe all waveforms for TP1, TP2, TP3 & TP4 for both +ve & -ve outputs, by rotating pot P1 in clockwise and anticlockwise direction respectively. ECE121 Experiment No. Figure 1 shows the schematic arrangement of a dual converter. Field effect transistors, on the other hand do not normal require any input current and are unipolar devices. 3 - SCR AC Power Control, ECE121 Experiment No. RC Triggering Circuit – HWR & FWR 19 6. An electron movement in the n-channel, in turn causes substantial hole injection from p+ substrate layer into epitaxial n- layer. e) Record in Table 8-1 the data for this triggering mode of Q1. Remove the gate supply permanently. 2 - SCR Gate Characteristics. R.M.Shaikh/Prof.A.S... Analog Electronics Lab Manual Experiment No 1-5, Analog Electronics Lab Manual Experiment No 6-11, Analog Electronics Syllabus Wise e-Resources links. Because they also demand no input current, they are easier to drive. Observe the waveforms and plot it for one particular firing angle by adjusting the potentiometer and observe the range over which firing angle is controllable. The characteristics of a TRIAC are similar to those of an SCR, both in blocking and conducting states, except for the fact that SCR conducts only in the forward direction, whereas the TRIAC conducts in both the directions. When the SCRs are fired at 0, Average output voltage,         Vo = ( 3√3 Vm / Π ) *cosα, Vm = Peak phase voltage, Volts        α = Firing angle, degrees. At ωt = α, SCRs T1 and T3 are triggered, then the current flows through the L – T1- R load – T3 – N. At ωt = π, supply voltage falls to zero and the current also goes to zero. A. (Marked  NORMAL). The purpose of a dual converter is to provide a reversible DC voltage to the load, typically a separately excited DC motor. 4. f) Connect the oscilloscope across DS1 to monitor the load voltage. Other details remain the same as for delta connection calculations. For reverse characteristics, change the connection to make M. 2. Explain the operation of single phase Dual Converter, What are the application of single phase   Dual converter, What is the difference between dual converter and Cycloconverter, 209--Power system lab Manual by Prof.Mrs. Here, output voltage is either positive or negative but output current is always positive. 8-3. b) Adjust the main terminal voltage to 6.3 Vac. Resistor R1 lowers Vdc to a suitable value for the zener diode and UJT. 3. 4. Ensure pot P1 in zero position & SW3 is in downward (NORMAL) position. e) Record the data for this triggering mode of Q1 in Table 8-1. The force acting tangentially on the pulley is equal to the difference between two spring balance readings. Yes. 1. Its primary function is to control power bilaterally in an AC circuit. SCR Characteristics 3 2. To obtain V-I characteristics and to find on-state forward resistance of given SCR. In operation triac is equivalent to two SCRs connected in anti-parallel. Once the gate V. For a DIAC, there is a breakover voltage present in either direction. d) Look at your circuit and then record in Table 8-1 the triggering mode of Q1 in this configuration. SCRs T3 and T4 forward biased. e) Record the characteristics of this Q1 triggering mode in Table 8-1. f) Open S2 and reduce all voltage sources to zero. What are the effects of source inductance on the output voltage of a rectifier? To conduct the performance of single phase fully controlled bridge converter. It houses transformers for control circuit & 1 no of power transformer (0-130 v AC secondary o/p, 2 Amps), for energizing the power circuit. Keep CHOKE /NO CHOKE mode as per desired mode of operation. Connect a & k terminal of UJT triggering circuit to the gate cathode terminals of SCR. It was also initially called insulated gate transistor (. Typical time /division for measurement is 1 msec/di. Objective B. ü Power Source 6.3 Vac, 500mA, ü Power Source 6 Vdc, 500mA, ü C1 0.1μF, electrolytic, ü DS1 Miniature lamp, ü Q1 DIAC, ST2, ü R1 47Ω, 1W, ü R2 10KΩ, 1W, ü S1 PBNO, ü S2 SPST. Switch on the power supply to the CRO . Vary the voltage applied across Gate and corresponding  V, 5)     The above steps are repeated for different values of I, 6)     Vary the voltage across Collector and Emitter and noted down V, TRANSFER CHARACTERISTICS                                    DRAINCHARACTERISTIC. Its three terminals are usually designated as MT1, MT2 and gate. IGBT is also known as metal –oxide insulated gate transistor (MOSIGT), conductively –modulated field effect transistor (COMFET) or gain –modulated FET (GEMFET). 1-6 2 Static characteristics of MOSFET & IGBT. This switch should be normally in downward position. The electric supply system can be classified into i) d.c. or a.c. system (ii) overhead, Experiment no. Switch on the TRIAC knob and firing circuit kit. When gate is positive with respect to emitter and with gate-emitter voltage more than the threshold voltage of IGBT, an n-channel is formed in the p – regions as in a power MOSFET. Connect the three phase 440 volt supply to the rear of the instrument using the terminals marked R,Y,B .Connect Load bank. The n+ layer substrate at the drain in power MOSFET is now substituted in the IGBT by a p+ layer substrate called collector. … An SCR is a three terminal, four layer latching device. They involve a single conducting channel which can be either N or P type material. 2. Initially connect for delta operation.. Keep load control pot in minimum position. 2. Only a small leakage current flows through the device. iv List of Experiments Exp No Experiment Nmae Page No 1 Static characteristics of SCR and DIAC. The field supply during this process remains connected. Why? What is the condition for load current should be discontinuous? TP2(red) and Green( - ve of CRO):- Attenuated output for CRO. Thank you. Temperature rise of machine can be noted. Rotate the pot P1 to zero position & turn it in clockwise direction the motor starts rotating in clockwise direction. Why i-mode is more sensitive among all modes? Hence SCRs T1 and T3 turned off. What are the disadvantages of unidirectional controllers? This n-channel short-circuits the n- region with n+ emitter regions. 2. Would you say that TRIAC has four separate and distinct triggering modes? 2. Then switch on the power for electronic and control circuit. Make the connections as per the circuit diagram. Triacs are widely used in AC power control applications. The symbol and pin out of TRIAC is shown below. The Conduction Current rises quickly and hence Resistance is connected in series with a DIAC for a safe operating level of the circuit. 16-19 4 20 AC- voltage controller by using TRIAC-DIAC combination.-22 5 UJT firing circuit for HWR & FWR. Observe that capacitor voltage is set at every half cycle. 8. Observe the current when the device turns OFF. (LC Commutation Circuit) Oscillation Chopper Circuit 29 8. For lamp load a separate load bank is provided. With RL- load it becomes a two-quadrant converter. Note that there are separate switches are provided for electronic circuit ON/OFF and control circuit ON/OFF. Ring main system 5. Explain the different working modes of operations of a TRIAC? The characteristics of a TRIAC are similar to those of an SCR, both in blocking and conducting states, except for the fact that SCR conducts only in the forward direction, whereas the TRIAC conducts in both the directions. Different information/references for different major subjects of this course are made available for them. During the positive half cycle, SCRs T1 and T2 are forward biased. Characteristics of a Triac First Quadrant Operation of Triac. There is however; a major difference in the substrate. Triac is the word derived by combining the capital letters from the words TRIode and AC. EXPERIMENT-1(a) V-I CHARACTERISTICS OF SCR AIM: 1. You must not observe the waveforms for triggering circuit & output simultaneously on CRO. V-I characteristics of TRIAC are obtained. Define Holding current, Latching current on state resistance, Break down voltage, 3. Objective A. As a result of their performance, trials tend to be used for low to medium power applicati… 2. a) Change your circuit that shown in Fig. To study Three Phase Converter (Half Wave and Full wave Bridge). It exhibits negative resistance characteristics. ☞Increase VAK voltage to maximum position. What are the advantages of six pulse converter? Demonstrate the four triggering modes of a TRIAC. : keep motor running at  about 100 v with negligible load on the motor. The system to demonstrate the functioning of this 1 phase dual converter is housed in a sturdy MS powder coated box. When reversal of output is required, the firing pulses for the conducting bridge are stopped and the second bridge is gated. 1) Select Triac as the device under test by referring to the top RHS diagram. The circuit symbol and schematic construction of one such device are shown in fig.1. A V-I Characteristic of SCR (Silicon Controlled Rectifier) is the Depletion mode operated devices are normally in ON condition. The thyristor must be fully ON. UJT Triggering of SCR – HWR & FWR 33 9. 4. Experiment Steps ☞Connections are made as shown in the circuit diagram. The power enhancement MOSFET has an anti parallel fast turn on diode which permits reverse current of the same magnitude as that of the main MOSFET, so that drain substrate junction will not be damaged when drain and source has reverse biasing. A metallic gate is deposited on the thin layer of metal oxide (insulator) which is deposited on the channel opposite to the substrate. Since the TRIAC is a bi-directional device the current can either flow from MT1 to MT2 or from MT2 to MT1 when the gate terminal is triggered. For large power dc loads, 3-phase ac to dc converters are commonly used. This allows the component to conduct in both directions. The various types of three-phase phase-controlled converters are 3 phase half-wave converter, 3-phase semi converter, 3-phase full controlled and 3-phase dual converter. NV6532 TRIAC Characteristic Trainer 2. Study the waveforms for various firing angle by varying the pot in R trigger circuit. ☞Set both voltages to minimum position, and then switch on SPDT. R2 is the variable resistance. It’s Voltage to Current (IV) Characteristics is as shown in the Fig below. A synchronized UJT triggered circuit using an UJT is shown in the figure. However a large input signal may momentarily overcome the reverse bias and turn on gate diodes drawing appreciable current from the source. Verify Edc as shown from the panel voltmeter for this setting. The anode current must be more than a value known as latching current in order to maintain the device in the ON state. Note MT1, MT2 & gate terminals properly. So as IGBT has input impedance like a MOSFET and low on-state power loss as in a BJT. 4. As the name indicates, a dual converter consists of two converters (single phase or three phases), both either fully controlled or half controlled connected to the same load. The FETs offer advantages in switching service since they do not suffer the delays associated with minority carrier storage. i.e. To study single phase fully controlled bridge converter. The attenuator o/p can be observed on CRO. 1. a) Connect the circuit shown in Fig. Be sure S2 is open initially. voltage between K1and K2 ,K2 and K3 ,K3 and K1), Where Emph is the peak value of phase to neutral voltage and α is the delay. The device will be in the reverse blocking state and small reverse leakage current flows through the device. What are the two modes of operation present in the three phase half controlled rectifiers? To study the characteristics of single phase dual converter, 1. 1) Select Triac as the device under test by referring to the top RHS diagram. The DC motors are undisputable electrical equipments in any application. Its three terminals are MT1 (main terminal 1), MT2 (main terminal 2) and G (gate). It is used extensively for the control of power in ac circuit as it can conduct in both the direction. D.C .Radial Distribution System 3. If lamp is removed & the same process is repeated with motor running, you notice that motor take longer time to stop. Start the P1 from zero , you may need to adjust “P2’ slightly .Slowly increase the speed. LIST OF EXPERIMENTS 1. Disclaimer: Not all information posted in this site are accurate. In the middle (marked zero position) none of the pulses for triggering the thyristors are generated. g) Look at the recorded data of Table 8-1. A.C. Distribution Radial System 4. Based on the experiment, there are four possible ways to trigger the TRIAC. MOSFET Characteristics 15 4. At ωt = π + α, SCRs T2 and T4 are triggered, then current flows through the path N – T2 – R load- T4 – L. At ωt = 2π, supply voltage and current goes to zero, SCRs T2 and T4 are turned off. 1.2 To measure the gate trigger voltage and the holding current of a typical SCR by using dc measurement methods. Semi converters and full converters are quite common in industrial applications. Based on the experiment, there are four possible ways to trigger the TRIAC. 6. Explain how synchronization of the triggering circuit with the supply voltage across SCR is achieved? To plot the output waveforms of single phase fully controlled bridge converter, 1- Ф fully controlled bridge converter(kit). 9. 7. Sheet Report 1 Object Power System Components Objectives To study- 1. 8. Resistance trigger circuits are the simplest & most economical method. Maximum triac current, voltage across the triac and gate current limit is 600mA, 30V and 20mA respectively. 1. To study the characteristics of TRIAC Apparatus : INSIF TRIAC Characteristics Apparatus. Now connect for star connection .Connect lamp load bank .Do not connects motor when system is in ‘Star connection’ In this case the line voltage will be 140 volts. 6-12(b) is the symbol for triac. 4. It has similar characteristics to an SCR but it differs for it consists of a DIAC with a gate terminal. Switch ON the supply. A fully controlled converter or full converter uses thyristors only and there is a wider control over the level of dc output voltage. For firing angle less than 30°, the output terminal voltage of the converter is always positive, and the freewheeling diode does not come into operation. When you move pot P1 in clockwise & anticlockwise direction, voltage polarity is indicated by voltmeter. Like a power MOSFET, an IGBT has also thousands of basic structure cells connected appropriately on a single chip of silicon. b) Adjust the main terminal and the gate voltage sources to +6Vdc. Now turn OFF power circuit & connect the motor to the output socket with no load on the motor. You may observe o/p waveform across the attenuated test point for o/p. It can operate and switch both half cycles of an AC waveform. When the anode to cathode voltage is increased to break-over value, the junction j2 breaks down and device starts conducting. As the current ‘i2’ is in the form of pulse, windings of the pulse transformer have pulse voltages at their secondary terminals. All the eight thyristors (TYN 612) are grouped into two sections are for +ve o/p & for –ve output (4 no of each group). The switch SW3 is required to be kept in downward position for normal-dual converter operation. B. Bring pot P1 to zero position & turn ON switch SW2 for power circuit, the thyristor circuit is energized & you can observe the lamp intensity control. Steps No.2, 3, 4, 5, 6, 7, 8 are repeated for another value of the gate current I, Note: - Follow the same design procedure for TRIAC connection sting, 1. Take down the readings in tabular form and analyze. It produces a sawtooth waveform that when polarity is reversed, an inverted sawtooth is displayed on the oscilloscope. 1. 1 Object Load test on DC Shunt motor. Does DS1 light? What is the condition for the output voltage should be negative? What are the effects of load inductance on the performance of AC voltage controllers? Circuit Diagram : Theory: An TRIAC is a device which can be turned on through the gate pulse for both positive and negative values of V AK and turned off using power circuit i.e., turn on is controlled … The main advantage of this system lies in the smallest time interval during which motor can be brought to rest. Thereby facilitating conversion of DC power onto AC. Compare UJT triggering circuit with RC firing circuit? Load the motor & observe the effect on the o/p waveform across attenuated output test points. Then throw the switch SW3 in upward position. For motor to start running you have to take pot P1  to most anticlockwise position. Interconnected System Theory The conveyance of electric power from a power station to consumes’ premises is known as Electric supply system. the power station, the transmission lines, and the distribution system. 2mm Patch cords. The invention of the TRIAC was necessitated because of the need for controlling power fed to ac loads. What are the advantages of three phase rectifier over a single phase rectifier? Aim : To study the V-I characteristics of TRIAC. In this system when the motor is required to be braked, the pulses for the bridge working as converter are blocked and the other bridge is operated in inverter mode. If JFETs are operated with reverse bias on their gate leads to prevent gate current. These are only for reference and comparison. MOSFETs are operated in depletion mode as do JFETs with negative voltage on the gate terminal for N channel device. You may have to adjust pot marked “ADJUST” to get DC output voltage between approximately 50 volts D.C. to 175 volt D.C. You may observe the waveforms at TP1, TP2 and TP4. Calculate the dc output voltage using the equation. The first quadrant is the region wherein MT2 is positive with respect to MT1 and vice-versa for the third quadrant. 1. Labels: diac, ece121 industrial electronics, experiment, triac, where can i get a copy of the picture of the figures? We now know that a “triac” is a 4-layer, PNPN in the positive direction and a NPNP in the negative direction, three-terminal bidirectional device that blocks current in its “OFF” state acting like an open-circuit switch, but unlike a conventional thyristor, the triac can conduct current in either direction when triggered by a single gate pulse. The triac has on and off state characteristics similar to SCR but now the char acteristic is applicable to both positive and negative voltages. Characteristic # 1. The V-I characteristics of triac in the first and third quadrants are basically equal to those of an SCR in the first quadrant. Objective C. Demonstrate bi-directional operation of a DIAC. The characteristics of a TRIAC are similar to those of an SCR, both in blocking and conducting states, except for the fact that SCR conducts only in the forward … At any time, one SCR from each half conducts when there is current flow. The forward voltage drop across the device in the ON state is around one volt. Operating characteristics of triac in the 1st and 3rd quadrants are similar but for the direction of flow of current and applied voltage. h) Measure the peak waveform as in step (c) above. Those FETs that use this technique are known as metallic oxide semiconductor field effect transistor or MOSFETs. b) Reverse the polarity of the main terminal voltage by reversing the power supply leads connected to your circuit. characteristics by using two transistors analogy. The advantages of three phase converters over single-phase converters are as under: In 3-phase. A three-phase fully-controlled bridge rectifier can be constructed using six SCRs. i) Is the break over voltage approximately the same value in both directions? The Fig-3, shows the current and voltage waveforms for this circuit. Name the three regions of operation in an IGBT. Switch ON the power supply ON/OFF switch. Voltage 2. You may calculate the delay angel of the firing .Refer to the formula given below. For a TRIAC this tr… In more sophisticated systems the stored mechanical energy instead of being dissipated is returned to the AC mains by using what is called as regenerative braking system for dual converters. A electrical supply system consist of three principal components viz. Positive or negative potential across the terminals can be triggered by reaching +/- breakover voltage. 3. a) Reduce the gate voltage supply to zero. c) Adjust the gate supply voltage to 6 Vdc. Connections are made as per the circuit diagram. You can observe waveforms TP2 and TP4 with Motor as load. Is the voltage waveform a complete sine-wave? Measure the dc plus peak waveform across CR1. Voltage at terminal MT 2 is positive with respect to terminal MT 1 and gate voltage... Second Quadrant Operation of Triac. TRIAC is only used in AC circuits. d) Close S2 and depress S1 momentarily. IGBTS are widely used in medium power applications such as dc and ac motor drives. Figure shows the quadrant operation of fully controlled bridge rectifier with R-load. When in operation, a TRIAC is equivalent to two SCRs connected in anti-parallel. d) Depress and hold S1. When ac voltage is supplied across the terminals of the bilateral gated TRIAC, it is shorted, wherein a complete sine-wave input is supplied across the load to the TRIAC. Now gradually load the motor and take ,speed, current voltage readings. c) Adjust the main terminal voltage to -6Vdc. 1. APPARATUS REQUIRED: Trainer kit, Patch cards, Multimeters. To see the phase controlled converter output waveform, use a 230 / 12 V transformer for isolation purpose. The V-I characteristics of a TRIAC is based on the terminal MT1 as the reference point. Results are accurate. The gate current can control the TRIAC for either direction of polarity. It can be triggered by reaching its breakover voltage (+ or -). 10.Conduct an experiment to produce variable DC o/p voltage (chopper), plot o/p voltage v/s duty cycle for Variable frequency & Fixed Frequency. A TRIAC is a bidirectional thyristor (it can conduct in both directions) with three terminals. 4 - Unijunction Transistor, ECE121 Experiment No. Fig. Generally power enhancement MOSFETs are used in power electronics circuits. 4. Adjust gate voltage to a slightly higher value than what is found in (a) set, Increase the anode current from latching current level with pot or by increasing the supply voltage slightly. With pure resistive load, it is single quadrant converter. Plot the graph of VORMS v/s 〈. For motor load 12 pin socket is provided with 110 v DC motor. Capacity 3. Nvis 6530A Understanding Characteristics of DIAC, TRIAC & SCR is remarkable and frequently used laboratory equipment which is designed to explain fundamentals and working of DIAC, TRIAC & SCR. Triac is a bidirectional thyristor with three terminals. 6-12(a) and attaching 2 main electrodes and 1 gate electrode. Disadvantages, To study SCR/TRIC/ DIAC/ MOSFET/IGBT Characteristics. 6 - UJT-SCR Time Delay Circuit, ECE121 Experiment No. Set the gate current at a fixed value by varying RPS on the gate-cathode side. What are the advantages of ON-OFF control? DIAC can be tested by applying about 32 volts across its terminals with both the polarities, including the limiting resistance of 2K in series with M3 meter. 4. Power IGBT is a voltage controlled device? d) Reduce the power supply voltage to zero. The anode current through the device at this instant is the holding current (I. Triac means the device for AC control composed of 3 electrodes. What is a three phase controlled rectifier? You can repeat the sequence when you rotate the motor in anticlockwise direction also. 05-09 3 Controlled HWR and FWR using RC triggering circuit 10-14 4 UJT firing circuit for HWR and FWR circuits 15-20 5 Generation of firing signals for thyristors/ trials using digital circuits / microprocessor. Explain the working operation of V-I characteristics of S.C.R. 3. 5. Triac can be triggered by both positive and negative polarity voltages applied at the gate. 2. What are the different types of Power IGBT? 4. a) Reduce the main terminal supply voltage to zero. It can be triggered by reaching its breakover voltage (+ or -). 2. 1. The armature will be disconnected from power circuit & connected to lamp load which is located on the right hand side socket. It is transmitted over large distance to load centers with the help of conductors known as transmission lines. By varying the anode- cathode supply voltage V. 6. IGBT Characteristics 17 5. Why? In the forward direction, the shape of the output characteristics is similar to that of BJT. Three phase half controlled bridge rectifier circuit consists of three SCRs in three arms and three diodes in the other three arms. As the pot P1 is moved clockwise or anticlockwise, the phase angle for reference pulse & triggering pulse goes on varying. It is an open loop system based on a dual converter using non circulating current mode of operation. Its equivalent circuit is a pair of inverted four layer diodes. A gate current of specified amplitude of either polarity will trigger the TRIAC into conduction in either quadrant, assuming that the device is in a blocking condition initially before the gate signal is applied. UJT Triggering of SCR 23 7. SCR with positive anode voltage would turn ON. 3. 01-04 2 Static characteristics of MOSFET and IGBT. 3. Apparatus Required : 1. 1. This is the break over voltage of CR1. What is commutation angle of a rectifier? The on state resistance can be calculated from the graph by using a formula. Diodes ‘D1’ to ‘D4’ rectify ac to dc. With motor load connected, the switch SW3 if then in upward position, connects the armature circuit to lamp load (ensuring that thyristor o/p is disconnected), the stored KE in motor rotor is converted into DC voltage which lights the lamp momentarily & dissipates all the stored energy in the motor rotor in the lamp load & motor comes to halt immediately, indicating the process of dynamic braking. 3. If thyristor does not turn off even after pot is at the highest resistance value, then reduce anode supply voltage. You can observe various test points as described. Measure the average dc voltage across the load and rms value of the ac input voltage using g' DMM, 10. When the cathode voltage is made positive with respect to the anode voltage the junction j2 is forward biased and the junction’s j1 and j3 are reverse biased. IGBT is constructed virtually in the same manner as a power MOSFET. This is expected because triac consists of two SCRs connected in parallel but opposite in direc tions. Any type of motor Shunt, Series or Compound can be tested. b) Reverse the polarity of the gate voltage supply again. The peak voltage applied across the device in either direction must be less the break over voltage in order to retain control by the gate. It is a three terminal switching device similar to SCR (Thyristor) but it can conduct in both the directional since it construct by combining two SCR in anti-parallel state. ADVERTISEMENTS: There are three important characteristics of an accumulator (or storage battery) are: 1. C. Demonstrate bi-directional operation of DIAC. 7. When the anode is more positive  with respect to the cathode. In the former, only one of the bridges is triggered. Vm = Peak phase voltage, Volts , α = Firing angle, degrees, TP1 (red) and Ground (Black) :- UJT Relaxation oscillator output. g) Is the polarity of the sawtooth inverted? Thus stored KE will be converted into electric energy & lamp will glow momentarily & motor comes halt immediately. Objectives To study the direct loading test of DC Shunt motor by Rope-Pulley arrangement method. Write down the expression for average output voltage of three phase full converter. 2. 2. To study UJT trigger circuit for half wave and full wave control. ; V GT is a range of gate voltages that will trigger conduction. To understand performance of SCR/TRIAC/DIAC/MOSFETS and IGBT. Yes. The value of emf of a cell does not remain constant but varies with the change in specific gravity of electrolyte, temperature and the […] Sufficient dead band for the generation of pulses for either +ve o/p (clockwise movement of P1) or –ve o/p (anticlockwise movement) of pot P1. 8-5. 2. ... like a triac without gate terminal, as shown in figure. Due to insulated gate, negligible gate current flows. Observe the range of firing angle control. To study V-I characteristics of SCR and measure latching and holding currents. The SCRs are triggered in the sequence T1, T2, T3, T4, T5, T6 and T1 and so on. Note MT1, MT2 & gate terminals properly. The firing angle can be controlled up to above 150o. 1 Thyristors DC Characteristics PREPARED BY: J.B. G. Ibarra 1.0 OBJECTIVES 1.1 To become familiar with the characteristics of the (SCR) silicon controlled rectifier and its operation. Before you switch on the power, connect motor cable (12 pin johson cable) and proximity switch cable (3 pin socket) correctly. In DC applications, SCRs are required to be connected with a parallel diode to protect against reverse voltage. The three terminals are anode, cathode and gate. 2) You have to follow general test procedure as per, It indicate the variation of drain current I, This characteristic shows the variation of drain current I, Output characteristics of an IGBT show the plot of collector current IC versus Collector-Emitter voltage V, The transfer characteristics of an IGBT is a plot of collector current I. What are the differences between SCR and TRIAC? 1. Eventually a forward current is established as shown in fig. Fig. The two modes of its operation are non-circulating current mode and the circulating current mode. 2 main electrodes and 1 gate electrode calculated from the channel with a thin layer of silicon dioxide ( oxide... 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Of three-phase phase-controlled converters are 3 phase half-wave converter is rarely used in power Electronics circuits typical! Circuit symbol and schematic construction of one such device are shown in first!