Laboratory 1: MOSFETsIntroduction!e objective of this laboratory is to explore the operation and device characteristics of an N-channel, enhancement-mode MOSFET. !e speci"c device you will be using is the Fairchild 2N7000.

Part A: Laboratory Preparation1. Using the information in the attached datasheet for the 2N7000, estimate the transconductance

parameter [kn’ (W/L)] for this transistor.

2. For the circuit in Figure 1, what are the possible modes in which the transistor can operate?

Part B: In the Laboratory1. Using the circuit shown in Figure 1, determine the threshold voltage (Vt) of your

transistor.

2. Measure the transconductance of your transistor and compare it to the value calculated in Part A.

3. Construct the circuit of Figure 2, and sketch the VDS versus VGS curve for your circuit (with vgs = 0). Identify and label the transition points between the cut-o!, triode, and saturation regions.

4. Select an appropriate bias value (VGS) value for your circuit, based on your results from step 3.

5. Using a function generator, apply an input signal (vGS = VGS + vgs) and determine the voltage gain Av of your transistor ampli"er at the bias point you selected in step 4.

6. What is the maximum peak-to-peak amplitude of the small-signal input vgs that can beapplied before you observe non-linear behaviour in the output waveform?

7. How is the operation of the circuit a!ected by changes in RD and VDD.

ECE 3670 Electronics III Laboratory 1

1 Fall 2012

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Figure 1

Figure 2