Electrical

Merits, Demerits and Applications of Power MOSFET Merits of a Power MOSFET (Advantages of MOSFET) The input resistance of MOSFEs is high and they are voltage controlled devices. Therefore the gate driving circuit for MOSFET is simpler. Power MOSFETS can operate at high switching frequency (typically upto 100 kHz). This is due to the fact … Read more

Transfer Characteristics of n-channel Enhancement Type MOSFET The transfer characteristics of a n-channel enhancement MOSFET are as shown in Figure. Note that the drain current is zero for VGS ≤ VTN For an n-channel E-MOSFET the threshold voltage is denoted by VTN and for a p-channel E-MOSFET the threshold voltage is denoted by VTP. The transfer characteristics shown … Read more

I-V Characteristics of MOSFET (Output Characteristics) 1. The I-V characteristics (output characteristics) of power MOSFET is shown in Figure. The source terminal is common between the input and output of the MOSFET. The output characteristics is a graph of drain current iD versus drain to source voltage VDS for different values of gate to source voltage VGS as … Read more

MOSFET Working Principle of Operation With gate to source voltage VGS = 0 the MOSFET is equivalent to two back to back diodes connected as shown in Figure (a). The diodes are formed between n+ and P layers as shown. The basic structure of MOSFET is very much similar to the BJT. The only difference is the … Read more

Simplified Structure of Power MOSFET Figure (A) shows the simplified structure of power MOSFET and Figure (B) shows the circuit symbols. Figure (A) Figure (B) The n+ p n– n+ structure shown in the Figure (A) is ow termed as enhancement mode n channel MOSFET. A structure of a p-channel MOSFET has exactly the opposite doping profile. The doping … Read more

Structure of a Power MOSFET Structure of a power MOSFET : The power MOSFETS are generally enhancement type. In order to increase the voltage rating of the enhancement MOSFET, a drift layer is included as shown in Figure. The power MOSFET has the vertically oriented four layer structure of alternate p and n layers as … Read more

Power MOSFET The long form of MOSFET is Metal Oxide Semiconductor Field Effect Transistor. The new power MOSFETS have improved current carrying capacity and higher off state blocking voltage capacity and they are replacing the power transistors in many applications. Power MOSFETS are capable of switching at very high frequencies upto about 100 kHz. This … Read more

Advantages of SCR It can handle large voltages, currents and power. The voltage drop across conducting SCR is small. This will reduce the power dissipation in the SCR. Easy to turn on. Triggering circuits are simple. It can be protected with the help of a fuse. We can control the power delivered to the load. … Read more

Operation of SCR : Operation of SCR can be studied under two different operating conditions. They are as follows : SCR Operation without gate current : Refer to Figure (a) The gate terminal of SCR is left open so that IG = 0. SCR is forward biased by applying a positive voltage to anode with respect to … Read more