Simulation Practices for Electronics and Microelectronics
Engineering
Dr. Graciano Dieck Assad / Ing. Matías Vázquez Piñón
Review Activity
1.1 Basics on Spice Simulation for Electric Networks
1. For the DC bias point analysis, show the simulated voltage drop across R1 and R2. Does the
sum of both voltages correspond to the voltage supplied by the voltage source V1?
2. Change the resistance values to R1=500 Ohm and R2=1500 Ohm, and run a DC bias point
analysis again. How is the voltage supplied by V1 divided in this case? Demonstrate your
results using the voltage division equation:
𝑉𝑜𝑢𝑡 = 𝑉𝑖𝑛
𝑅2
𝑅1 + 𝑅2
3. For the transfer function analysis, show a print its results including the transfer function and
the input and output resistances of the circuit. You can derive the transfer function of your
circuit from the voltage division equation, as follows:
𝑉𝑜𝑢𝑡
𝑅2
=
𝑉𝑖𝑛
𝑅1 + 𝑅2
Solve the equation above, and compare your results to the transfer function obtained with
Spice. Also determine the input and output resistances of the same circuit, and compare your
results to the ones obtained with Spice.
4. Capture the series circuit shown below on LTspice. Using a bias point analysis (.OP), determine
the transfer function for node 3; that is V(3)/Vin. Also, obtain the input and output resistances
(seen by the voltage source and node 3, respectively). Verify your results using a transfer
function analysis (.TF).
Figure A. Series circuit
5. By means of simulation, find the DC current flowing through each resistor and through the
voltage source of the parallel circuit shown below. Determine the power dissipated or
absorbed by each component. Is the power dissipated by the voltage source equal to the
1
D . R . © I n s t i tu t o T e c no l ó g ic o y d e E s t u d i o s S u p er i o re s d e M o n te rr e y , M é x i c o 2 0 1 2
Simulation Practices for Electronics and Microelectronics
Engineering
Dr. Graciano Dieck Assad / Ing. Matías Vázquez Piñón
power absorbed by the three resistors? Explain your answer.
Figure B. Parallel circuit
6. For the transient analysis, show the voltages for V1, R1 and R2 from next figure:
Spice Deck Version
*01_sch_sine_waves.asc
V1 1 0 SINE(500m 1 100)
R1 2 1 100
R2 0 2 100
.tran 0 50m 0 100u
.backanno
.end
Schematic Version
Figure C. Schematic capture and Spice deck of a voltage divider circuit with a transient analysis setup
Is the sum of V(R1) and V(R2) equal to the voltage supplied by the voltage source V1?
Demonstrate your results using the voltage division equation.
7. Show the measurements performed with Spice for the amplitude and RMS values of the
analyzed circuit. Demonstrate that the RMS value is correct using the corresponding
mathematical procedure in paper.
8. If, instead of a sinusoidal waveform, you use a square waveform, which equation would you
use to measure the RMS value? Make the corresponding changes in your circuit and
measurement directives, and demonstrate your results with a mathematical analysis in paper.
2
D . R . © I n s t i tu t o T e c no l ó g ic o y d e E s t u d i o s S u p er i o re s d e M o n te rr e y , M é x i c o 2 0 1 2