Chapter 14, Problem 10CDQ

3) A circuit is given as shown. (a) Find and label the circuit nodes. (6) Determine V2, V2, I₂, I₂ and Is © For each circuit element determine how much power it Supplies 15 absorbs. m 20 + 20 www 13 + 20 Z9V H 56 +1 LOV 1/2 1 4A + 3_22 3.2 ми + V₂ I 1

In this experiment, we are going to use a 2N3904 BJT. Examine the data sheet for this device carefully. In particular, make a note of the current gain (identified by hFE). 1. Obtain the curve trace for a "Darlington Pair" of Bipolar Junction Transistors. A Darlington Pair consists of two transistors with the first BJT driving the base terminal of the second transistor as shown in Figure 1 below. A. Set up the primary sweep voltages for V1 the same as shown in the lecture notes (see the Darlington pair IV curve). B. Set up the secondary sweep currents for 11 to be an order of magnitude smaller than for the single BJT. In the Sweep Type box choose linear and enter the following 3 values: Start Value: 0, End Value: 8u and Increment: 1u (see lecture notes). C. Describe the primary differences you observe between the single BJT Curve Trace and that of the Darlington Pair. Discuss what might cause each difference. Q1 11 Q2 V1 Q2N3904 Figure 1. A Darlington Pair of 2N3904 transistors in a…

2. Using the IV plots shown in Fig. 3 (and found in the reintroduction to PSpice) design a BJT biasing circuit that results in the following parameters: VCE = 2 Vand ig = 40 μA. We also require the power supply to be fixed at 5 Volts (this is where the load line intercepts the iB =ic = 0 line). You may use the circuit shown in Example 1. Note that all resistor values in Example 1 must be recalculated. Your solution for the base to ground and base to collector resistors may not be unique.

A circuit is given as shown. (a) Find and label the circuit nodes. (6) Determine I, I₁, I2 and V₂ I₂ +1 I 12V ww 22 2 ти + 보통 162 - ти 4 52 12 50 602 I 1 Mw

a) A silicon wafer is uniformly doped p-type with NA=10¹³/cm³. At T=0K, what are the equilibrium hole and electron concentrations?

1016 1015 Ge 101 Si 1013 1012 GaAs 10" (( uວ) uot¤ງແລ້ວuo ວາ.ຂ ວາsuuuT 0101 601 801 107 10% Determine the equilibrium electron and hole concentrations inside a uniformly doped sample of Si under the following conditions. (n; =1010/cm³ at 300K) a) T 300 K, NA << ND, ND = 1015/cm³ b) T 300 K, NA = 9X1015/cm³, ND = 1016/cm³ c) T = 450 K, NA = 0, ND = 1014/cm³ d) T = 650 K, NA = 0, ND = 1014/cm³ 10° 200 300 400 500 600 700 T(K)

b) A semiconductor is doped with an impurity concentration N such that N >> n; and all the impurities are ionized. Also, n = N and p = n2/N. Is the impurity a donor or an acceptor? Explain.

d) For a silicon sample maintained at T=300K, the Fermi level is located 0.259 eV above the intrinsic Fermi level. What are the hole and electron concentrations?

e) In a nondegenerate germanium sample maintained under equilibrium conditions near room temperature, it is known that n=10¹³/cm³, n = 2p, and NA 0. Determine n and ND.