MOSFET

MOSFET characteristic: The MOSFET is a four-terminal device, whose substrate, or body terminal must be always held at one of the extreme voltage in the circuit, either the most positive for the PMOS or the most negative for the NMOS. One unique property of the MOSFET is that the gate draws no measurable current. Methodology: 1. Built the circuit as shown in figure below figure. 2. For fixed value of VGS, vary the voltage VDS and note the corresponding current ID in table. 3. Now vary VGS and repeat step 2. 4. Note the behavior at VGS = 0v, VGS = VP and VDS = VP points. 5. Now, fix VDS > VP, note values of ID, for 0≤VGS ≤VP in table. 6. Draw Transfer characteristics (VGS vs ID). Transfer Characteristics: VGS (Volts)|VDS = 5 V (fixed) IDS (µA) 0.0 0 0.25 0 0.5 2.5 0.75 5.625 1.0 10 2.0 40 3.0 90 4.0 160 5.0 250 Conclusion: For MOSFET characteristics we can see the transfer characteristics in graph. when VGS = 0V current will increase till VGS = VT (Threshold Voltage) after this point current ID remains constant. When we fix VDS > VT and for 0 ≤ VGS ≤ VT current ID will increase as shown in transfer characteristics.