For the network of Fig. 169 : a. Determine Zi and Zo. b. Find Av.

Name: Problem 32, Chapter 5: Electronic Devices and Circuit Theory
Uploaded: 2025-09-13T18:39:32-08:00
Duration: 6 min 59 s
Channel: Susan Hallstrom
Description: For the network of Fig. 169 : a. Determine Zi and Zo. b. Find Av.

For the network of Fig. 169 : a. Determine Zi and Zo. b....

Key Concepts

Input Impedance

Input impedance refers to the effective resistance (or more generally, impedance) seen by an input source when connected to a network. It is a crucial parameter in circuit design that affects signal transfer, as it determines how much of the input signal is dropped across the circuit versus how much is delivered to subsequent stages.

Output Impedance

Output impedance is the impedance that a circuit presents at its output terminals. It plays a key role in determining how the circuit will interact with the load connected to it, influencing factors such as voltage division, power transfer, and overall frequency response.

Voltage Gain

Voltage gain is the ratio of the output voltage to the input voltage in a circuit, indicating how much the circuit amplifies the input signal. This parameter is fundamental in amplifier design and analysis, as it determines the level of signal amplification provided by the network.

Circuit Analysis Techniques

Techniques such as using Thevenin and Norton equivalent circuits are essential in analyzing networks to determine parameters like input impedance, output impedance, and voltage gain. These methods simplify complex networks into basic components, making it easier to predict circuit behavior under various operating conditions.

Transcript

00:01 In this problem, we have three things to do, a, b, and c, and i've gone ahead and draw the circuit.

00:09 So let's do a first.

00:13 For a, the first thing we're going to do is find r .e, which will equal, and we know that ib will equal v -c -e minus v -b -e, divided by r -b plus 1 plus beta, we will have 8 minus 0 .7 divided by 39 times 10 to the 4 plus 1 plus 120 times 5600 and this will equal 0 .828 and we'll have to go to millie amps.

01:08 So have a giant number.

01:11 So our e will equal 0 .828.

01:17 0 .026 over i .e which will equal 0 .026 over 1 plus beta i b which will equal 0 .026 over 1 plus 0 .828 times 0 .8 times 10 to the, let me see, where am i? this is micro.

01:58 This should have been micro, not milly.

02:01 My bad, 10 to the minus sixth, and this will equal 31 .4 oms.

02:13 Then, zi will be equal to rb, zb, and zb will be given as beta, r, e, plus beta plus 1 r e over 1 plus r e over r o and this will equal 120 times 31 .4 plus 120 plus 1 times 5600 divided by 1 plus 5600 divided by 4 times 10 to the 4 times 10 to the 4 this will equal 598 .16 kiloons.

03:20 So zi will equal 39 times 10 to the fourth times 2 30s, oops, my bad.

03:35 598 .16 times 10 to the third.

03:40 So my zi will equal 236 .1 kilooms.

03:48 There's my first part.

03:50 Now let's find our zo.

03:53 That'll be r e, r .e, and this will be 5 ,6001 .4.

04:10 So my zo will be equal to 31 .2 oms.

04:17 I hope i got that that one right...