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Which way does current flow in a MOSFET?
MOSFETs only switch current flowing in one direction; they have a diode between source and drain in the other direction (in other words, if the drain (on an N-channel device) falls below the voltage on the source, current will flow from the source to the drain).
How much current can MOSFET handle?
Modern MOSFETs can have on resistances of less than 10 milliohms. A little math shows that this device can handle 10 amps with one watt converted into waste heat (power = current2 x resistance). Since many MOSFETs come in TO-220 packages, no heatsink is needed in this instance.
Can a MOSFET conduct in both directions?
MOSFETs will conduct equally in both directions when they are turned “on.” An interesting consequence of the body-source connection is that, even if you turn the transistor “off,” it will still conduct in the reverse direction.
How are the drain characteristics of a MOSFET determined?
Hence with the change in voltage polarity both of the types can be used in both the modes. This can be better understood by having an idea on the drain characteristics curve. The drain characteristics of a MOSFET are drawn between the drain current ID and the drain source voltage VDS.
What happens when voltage is applied to a MOSFET gate?
In an enhancement mode MOSFET, voltage applied to the gate terminal can increase the conductivity from the “normally off” state. In a depletion mode MOSFET, voltage applied at the gate can reduce the conductivity from the “normally on” state.
How is the construction of a MOSFET similar to a FET?
Construction of a MOSFET. The construction of a MOSFET is a bit similar to the FET. An oxide layer is deposited on the substrate to which the gate terminal is connected. This oxide layer acts as an insulator (sio 2 insulates from the substrate), and hence the MOSFET has another name as IGFET.
Why is the same MOSFET used in depletion mode?
The channel nearer to drain gets more depleted than at source l i k e i n F E T and the current flow decreases due to this effect. Hence it is called as depletion mode MOSFET. The same MOSFET can be worked in enhancement mode, if we can change the polarities of the voltage VGG.