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Applet Worksheet

[This worksheet may be suitable for Computer Lab Recitation or for Homework assignment for introductory-level microelectronics courses.  If  you like, here is a MS Word file of this worksheet for three MOSFET applets.]

II. MOSFET: Channel Continuous (Triode mode) or Channel Pinched OFF (Saturation)
Applet: http://jas.eng.buffalo.edu/education/mos/mosfet/v11/mos_1.html
Applet Introduction:  This applet shows the Channel region versus the Gate-Source bias, Vgs, and the Gate-Drain bias, Vgd.  The I-V curves show the Id-Vds, the Drain current versus Drain-Source bias at all biasing conditions; and the Id-Vgs, the Drain current versus Gate-Source bias when the MOSFET is in Saturation.  The red-dot indicates the current Biasing condition.
3. N-channel

ix) Applet Preparation: Select N-channel, Vt=1.5 V ==>  Use Up/Down arrows to change Vgs and Vgd.  Set Vgd = 0V
x) Change Vgs and find at what Vgs the channel forms at the Source-end ?
Vgs = (    ) volts
xi) From the above, what is the relationship of Vgs vs. Vt for the N-channel to form at the Source-end ?
Vgs  vs. Vt:   (                                            )
xii) Now, change Vgd and find the Vgd value at which the Channel is continuous through the Drain-end (if  the channel is not continuous, then the channel is pinched off at the Drain-end):
Vgd = (          ) Volts.
xiii) From the above, give a relationship for Vgd vs. Vt for the N-channel.
Continuous Channel (Triode) :   Vgd vs. Vt ==>  (                           )
Channel is pinched off at Drain end (Saturation): Vgd vs. Vt  ==>  (                           )
Note the location of red-dot on the Id-Vds curve.  The red-dot is the current biasing condition Vgs and Vgd of the MOSFET.

4. P-Channel

xiv) Applet Preparation: Select P-channel, Vt= -1.5 V ==>  Use Up/Down arrows to change Vgs and Vgd.  Set Vgd = 0V
xv) Change Vgs and find at what Vgs the channel forms at the Source-end ?
Vgs = (    ) volts
xvi) From the above, what is the relationship of Vgs vs. Vt for the P-channel to form at the Source-end ?
Vgs  vs. Vt:   (                                            )
xvii) Now, change Vgd and find the Vgd value at which the Channel is continuous through the Drain-end (if  the channel is not continuous, then the channel is pinched off at the Drain-end):
Vgd = (          ) Volts.
xviii) From the above, give a relationship for Vgd vs. Vt for the P-channel.
Continuous Channel (Triode) :   Vgd vs. Vt ==>  (                           )
Channel is pinched off at Drain end (Saturation): Vgd vs. Vt ==> (                           )
Note the location of red-dot on the Id-Vds curve.  The red-dot is the current biasing condition Vgs and Vgd of the MOSFET.

[You may continue and complete the questions below.]

1. N-channel MOSFET

N-channel and set Vt = 1.5V, and fill in  the  table below with Saturation, Triode, and Cut-off, respectively.

 Vgs Vgd Operation Region 1.7 V 1.7 V Triode 2.5 V 2.0 V 2.5 V 0 V 1.3 V 1.0 V
2. P-channel MOSFET P-channel and set Vt = -2.0V ,and fill in the table with Saturation, Triode, or  Cut-off.
 Vgs Vgd Operation Region -2.1 V 0 V -3.0 V -1 V Saturation -3.0 V -2.5 V -1.5 V -1.0 V