Deepakkumar Yadav
Types of Choppers Q. Classify chopper based on output voltage and quadrants of operation. List any four applications of chopper. Q. Classify choppers based on quadrants of operation. Sketch only circuit diagram of each. Q. Classify choppers based on output voltage and quadrants of operation. List four applications of chopper. Q. State the classification of … Read more
Introduction of Chopper Q. Define chopper and list its applications (any three). Q. Define chopper. Differentiate constant frequency control technique and variable frequency control technique principle. Q. State the working principle of chopper. State control techniques used for chopper. Q. State working principle of chopper. Describe the constant frequency system of control technique of chopper. … Read more
Field Controlled Thyristor (FCT) It is a new developed thyristor which is also called as field controlled diode (FCD) or bipolar static induction thyristor (BSITH). Similar to the conventional SCR, FCT also can block the RU current flow for both polarities of anode voltage and allows only forward current to flow. Basic structure of FCT … Read more
SOA of MOS Controlled Thyristor (MCT) Figure shows the SOA of the MCT. It is limited by the maximum controllable anode current, maximum power dissipation and the maximum temperature of the device. With increase in anode cathode voltage, we must decrease the maximum current (derating) due to power dissipation. We may not need a snubber for … Read more
Static (I-V) Characteristics of MOS Controller Thyristor (MCT) In the static condition, the I-V characteristics of the MCT are similar to those of SCR and GTO. Switching Characteristics of MOS Controller Thyristor (MCT) MCT can change its state from ON to OFF or OFF to ON within 1 µsec. Figure (a) shows a switching circuit using … Read more
MOS Controlled Thyristor Precaution MCT works as a gate controlled device if its current is less than a value called peak controllable current. If we try to turn off the MCT when current through it is higher than its rated peak controllable current, then the MCT may get destroyed. Hence for higher values of currents, … Read more
MOS Controlled Thyristor (MCT) Construction of MOS Controlled Thyristor (MCT) MCT is a special device which has the characteristics of a four layer p-n-p-n SCR and a MOS – gate structure. The schematic diagram of an MCT is shown in Figure (a). Its equivalent circuit is shown in Figure (b) and circuit symbol in Figure … Read more
Operation of Static Induction Thyristors (SIT) Anode is connected to a positive voltage with respect to cathode and a positive voltage pulse is applied to the gates Figure (a). Figure (a) The depletion region is filled with carriers and the device is turned ON. The anode current flows from anode to cathode. Now refer Figure … Read more
Important characteristics of SIT (Static Induction Thyristor) Symbol of SIT Switching speed : 1 to 6 µS Voltage rating : upto 2500 V Current rating : only upto 500 A The biggest disadvantage of SIT is that it is extremely sensitive to the perturbations in the manufacturing process. Small variations in the manufacturing process can … Read more
Static Induction Thyristors (SIT) Construction and output characteristics A SIT or SI-thyristor, is a self controlled GTO like ON-OFF device. It is a three terminal device. The three terminals are Anode, Cathode and Gate. The characteristics of SIT are very similar to those of a power MOSFET. It is turned on by applying a positive … Read more