EE 3950 Lecture : Lecture7
Document Summary
Operation: apply vgs >vtr, electric field is generated in. Sio2: e- drawn into substrate form a channel between d and s p-substrate. Vtr threshold voltage: cutoff region (vgsvtr, vdsvtr, vds>(vgs-vtr)) Similar, but everything is opposite n-substrate, p-type drain and source vds. Alternative v-i equations (vp- pinch-off voltage = vtr, 2) vds: cutoff (vgsvp, vdsvp, vds>(vgs-vp)): Operation: ( 0. 7v: apply vbe, b e junction becomes forward biased, e- drawn from e to b (ib starts, some e- cross narrow b-region and flow into c (ic starts, increase ib ic increases ic. B-e junction is like a diode (0. 7v to turn on) Regions of operation: cutoff (vbevsat) vce, saturation (vbe=vf, vce=vsat) Add one extra pn- junction to a photodiode. Responds to both light li and current injected into the base ib.
