### PHYS 415 Electronics

#### Lab 1 Network Theorems

In this lab we will analyze the circuit shown in Figure 1 using the following;

Figure 1
1. Kirkoff's node law
2. Kirkoff's loop law
3. Superposition
4. Thevenin's Theorem
5. Norton's Theorem

#### Kirkoff's node law

The sum of the curents flowing into a node is zero.

With the output current Iout equal to zero, write an equation for the total current flowing into the node labeled Vout. Solve for Vout.

#### Kirkoff's loop law

The sum of the voltages around a loop is zero.

Again with the load disconnected (Iout = 0.) Add the voltages arround the outer loop (10V plus the voltage across R1 and R2). Assume a current I1 flowing clockwise around the first loop(Through the 10V supply, R1 and the 2mA current source.) Also assume a current I2 flowing clockwise around the second loop (the 2mA current source and R2.) Note that 2mA = I2 - I1.

Solve for I2 and for Vout.

#### Superposition Theorem

In a linear system the effect of a number of causes is equal to the sum of the effects of each cause acting individually.

Set the current source equal to zero (no current-open circuit). Solve for Vout due to the 10V voltage source. Set the voltage source equal to zero (no voltage-short circuit). Solve for Vout due to the current source. Add these two componets of Vout to find Vout.

#### Thevenin's Theorem

As seen from a terminal, any linear network appears to be a voltage source in series with a resistor.

Obtain theThevenin equivalent circuit for the crcuit shown in Figure 1 as seen from the Vout terminal.

Figure 2   Circuit under test and its Thevenin equivalent

#### Norton's Theorem

As seen from a terminal, any linear network appears to be a current source in parallel with a resistor.

Obtain the Norton equivalent circuit for the crcuit shown in Figure 1 as seen from the Vout terminal.

Figure 3   Circuit under test and its Norton equivalent

Simulate the circuit in Figure 1 using PSPICE.

Obtain plots of the output voltage Vout as a function of output current for the circuit and its Thevenin and Norton equivalents.

Breadboard the circuit. Take measurements to verify network theorems.