Characteristics of Power MOSFET

CHARACTERISTICS OF POWER MOSFET

AIM:

• To obtain the output characteristics of a power MOSFET.
• To obtain the transfer characteristics of power MOSFET.

EQUIPMENTS AND COMPONENTS REQUIRED:

THEORY:

The power metal oxide semiconductor field effect transistor (MOSFET) is a device derived from the field effect transistor (FET) for the use as a fast acting switch at power levels. Unlike the bipolar transistor, which is a current controlled, the MOSFET is a voltage controlled device. The main terminals are the drain and source. The current flow from drain to source is being controlled by the gate to source voltage.

The absence of any stored charge makes very fast switching possible, with on and off times being much less than 1µs. Above approximately 100V, the conduction losses are higher for the bipolar transistor, but the switching loss is much less.

In the drain characteristics of the MOSFET, at very low values of drain source voltage, the device has a constant resistance characteristic but at higher values of drain source voltage, the gate voltage determines the current. However in power applications, the drain source voltage must be small in order to minimize the on state conduction losses.

CIRCUIT DIAGRAM:

Sample Wave form :

PROCEDURE:

Set up the circuits shown in figure.

Drain characteristics: Set up the circuit as shown in figure. Adjust the gate source voltage slightly above the threshold voltage (around 3 to 3.25 V). Keeping V_GS constant, the variation of drain current with drain source voltage is noted. Repeat the experiment for different values of V_GS.

Transfer characteristics: Set up the circuit as shown in figure.Keeping V_DS constant, the variation of drain current with gate source voltage is noted. Repeat the experiment for different values of V_DS.(Dothe experiment for V_DS=10 V and 12V).

RESULT:

The drain characteristics and transfer characteristics of the given MOSFET are obtained.