How to find power MOSFET-Load

How to find power MOSFET-Load - can be read out of the plot...

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EECS 314 // HW 02 // How to calculate the power delivered to the load in a circuit with MOSFET © 2010 Alexander Ganago Page 1 of 1 In experiments with MOSFET, similar to those you did yourself in the DC lab, the supply voltage is maintained constant V dd = +6 V, while the V GS voltage is varied and the V DS voltage is measured. The plot below shows typical data. Note that V GS is the control voltage: no DC current flows through the gate terminal. At the same time, the voltage V DS directly relates to the power absorbed by the load. In this example, we use the plotted data and refer to the simplified diagram shown here. At V GS = 3.2 V, the voltage V DS
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Unformatted text preview: can be read out of the plot as ~ 5.8 V, thus from KVL, the voltage dropped across the load is (6.0 5.8)V = 0.2 V, and the power absorbed by the load as P LOAD = V dd V DS ( ) 2 R LOAD ~ 0.2 mW for the 200- load resistor. By contrast, at V GS = 3.8 V, the voltage V DS can be read out of the plot as ~ 0.2 V, thus the power absorbed by the load is ~ 168 mW, increased by a factor of ~ 840 (!!). Note that the 200- load resistance in this circuit was chosen to ensure that a 0.25-W resistor could be used safely even if the MOSFET resistance R X becomes zero. If the load can handle higher powers, its resistance can be reduced....
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