You should submit your completed assignment to your tutor, arriving no later than Wednesday 25th April, 2018.
Question 1 (carries 22% of marks)
(a)A specimen of p-type silicon is 6mm in length, 2mm in width and 1mm thick. Its electricalresistance is 300 ꭥ measured along the length at room temperature. Assume that the carrier mobilities in silicon at room temperature are micron =0.15. What is the value of the concentration of carriers in the silicon?
(4 marks)
(b)A silicon pn diode passes a current of 3mA under a forward bias of 0.6V. What is the magnitude of the diode current under a reverse bias of 0.6V? Assume K=40 V-1.
(4 marks)
(c )A p-channel depletion mode MOSFET has VT=+3 V.Find the value of VDS beyond which the device is in the saturated region of operation, when VGS=+1V.
(2 marks)
(d)Figure 1 shows a simple common-emitter switching circuit, driven from a perfect input square-wave signal VIN of zero source impedance switching between 0 V and +5 V.
What is the turn-on time ton of the output signal Vout?The remaining circuit parameters are: Cc=1.5 pF,Cc=2.5 pF,VCE=0.1 V,VBE(on)=0.7V,β=75,transit timeƮt=0.5 ns,saturation time constantƮs=25 ns.
(7 marks)
