Assignment
Silicon is doped with a group III element. The minority carrier concentration is 107/cm The concentration of majority carriers electrons/holes (circle one) is /cm3 and the doping concentration NA or ND (circle one) is approximately /cm3
A semiconductor might have ni ˜ 1010/cm3 For an insulator ni ˜ _____/cm3
What can we change to increase conductivity if n (or p) is fixed?
Write the expression for Capacitance of a parallel plate capacitor:
The PN junction sketched in Figure 1 has 22pF capacitance at 4v reverse bias. We might expect 11pF at a reverse bias of about ____ v.
We increase NA in Figure 1 by 10 without any other changes. The new capacitance at 4v reverse bias is expected to be about _____ pF.
One side of a PN junction is doped with 1015/cm3Al. Chose an element _____ and concentration _____/cm3 that results in a depletion zone as sketched in figure 1. For a symmetrical depletion zone, increase/decrease (circle one) the added element concentration to ____/cm3
A zener diode has breakdown voltage 3.2 volts. To increase the breakdown voltage to 4.5 volts, we should increase/decrease (circle one) the doping levels.
Write the expression below for the current through a forward biased PN diode.
The value of kT/q at room temperature ______ v. What is a typical value for the ideality factor n in the diode current expression, based on your lab measurements n˜ ______.
The output of a half wave rectifier power supply is shown in figure _____ and the output of a full wave rectifier power supply is shown in figure _____ . The variation in output voltage is called "ripple." If ripple is too large, we may reduce it with more ______.
