Lab 2 Report – DC and AC Analysis with PSpice Software

Bill Chun Wai Hung

29 June 2004

A. Describe the Set-up

There are two circuits that were investigated in this lab. One is a DC circuit analysis and the other is an AC circuit analysis. The set-up diagram and the source file for the PSpice software is shown below. In the diagrams, R is resistors, V is voltage source, C is capacitors, and D is diode

Part I. DC Circuit Analysis

*this is my DC circuit

*   Circuit Diagram

* 1--------(R1)-----2

* |                          |

* |                          |

*(V0)                (R2)

* |                         |

* |                         |

*  -----------------0 (Ground)

R1 1 2 1k

V0 1 0 5

R2 2 0 1k

.DC V0 0 5 1.0

*DC element start stop step

.PLOT DC V(1,0)

.END

Part II. AC Circuit Analysis

AC Circuit Analysis

*this is my AC circuit

R1 1 2 1k

V0 1 0 AC 1

*element Node+ Node- AC Amplitude sin(off-set, amplitude, frequence)

C1 2 0 1u

* 1--------(R1)----2

* |                         |

* |                         |

*(V0)                (C1)

* |                         |

* |                         |

*  ------------------0 (Ground)

.AC LIN 20 1 60000Hz

*AC Linear #-of-points Start Stop

.PLOT AC V(2, 0)

.END

Part III. Tran Analysis
TRAN Circuit Analysis

R1 1 2 1k

V0 1 0 AC 1 sin(0 1 10MEG)

*element Node+ Node- AC Amplitude sin(off-set amplitude frequence)

C1 2 0 1u

*   Circuit Diagram

* 1--------(R1)-----2

* |                         |

* |                         |

*(V0)              (C1)

* |                        |

* |                        |

*  -----------------0 (Ground)

.TRAN 1n 100n

*TRAN time-step Stop-time (start-time), in this case, 1 nano-second step add up to 10 micro second

.PLOT TRAN V(2, 0)

.END

B. Desbribe Inputs

Part I. DC Circuit Analysis

In the DC Circuit, there are 2 resistors each of 1 kilo ohms, 1 voltage source of 5 volt. The voltage across node 0 and 1 is measured, that is the voltage across resistor 1 and resistor 2 (R1 and R2).

Part II. AC Circuit Analysis

In the AC Circuit, the set-up is similar to the set-up in the Part I (See the diagram in Part A), except the resistor (R2) is replaced by a capacitor (C1) across node 2 and node 0. The voltage across node 0 and node 2 is measured, that is the voltage across the capacitor (C1).

Part III. Tran Analysis

In the transient analysis, the voltage source has defined a signal frequency by sin (0 1 10MEG), which means a sine function of frequency 10 mega herz, no offset, and with an amplitude of 1.

C. Describe What you Observe

Part I. DC Circuit Analysis

The output is consistent with the input. The input voltage of the voltage source is 5 volt, and the voltage across resistor 1 and 2 (R1 and R2) is also 5 volts. This is consistence ohm’s law of V=IR.

From the graph of simulation, the voltage drop across node 1 and node 0 can be seen. This diagram shows a linear voltage drop, and this is consistent with the ohms law V=IR for a circuit that consist of resistors (R1 and R2) and voltage source.

Diagram of Simulation for Part I. DC Circuit Analysis

V0          V(1,0)

(*)----------    0.0000E+00   2.0000E+00   4.0000E+00   6.0000E+00   8.0000E+00

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

0.000E+00  0.000E+00 *            .            .            .            .

1.000E+00  1.000E+00 .      *     .            .            .            .

2.000E+00  2.000E+00 .            *            .            .            .

3.000E+00  3.000E+00 .            .      *     .            .            .

4.000E+00  4.000E+00 .            .            *            .            .

5.000E+00  5.000E+00 .            .            .      *     .            .

- - - - - - - - - - - - - - - - - - - - - - - - - - -

Part II. AC Circuit Analysis

The result of the AC Circuit shows the behavior of a RC (Resistor and Capacitor) circuit. The graph shows the relationship between voltage and frequency.

Diagram of Simulation for Part II. AC Circuit Analysis

FREQ        V(2,0)

(*)----------    1.0000E-03   1.0000E-02   1.0000E-01   1.0000E+00   1.0000E+01

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

1.000E+00  1.000E+00 .            .            .            *            .

3.159E+03  5.032E-02 .            .         *  .            .            .

6.317E+03  2.519E-02 .            .     *      .            .            .

9.475E+03  1.680E-02 .            .  *         .            .            .

1.263E+04  1.260E-02 .            . *          .            .            .

1.579E+04  1.008E-02 .            .*           .            .            .

1.895E+04  8.399E-03 .            *            .            .            .

2.211E+04  7.199E-03 .           *.            .            .            .

2.526E+04  6.300E-03 .          * .            .            .            .

2.842E+04  5.600E-03 .         *  .            .            .            .

3.158E+04  5.040E-03 .         *  .            .            .            .

3.474E+04  4.582E-03 .        *   .            .            .            .

3.790E+04  4.200E-03 .        *   .            .            .            .

4.105E+04  3.877E-03 .       *    .            .            .            .

4.421E+04  3.600E-03 .       *    .            .            .            .

4.737E+04  3.360E-03 .      *     .            .            .            .

5.053E+04  3.150E-03 .      *     .            .            .            .

5.368E+04  2.965E-03 .      *     .            .            .            .

5.684E+04  2.800E-03 .     *      .            .            .            .

6.000E+04  2.653E-03 .     *      .            .            .            .

- - - - - - - - - - - - - - - - - - - - - - - - - - -

Part III. Tran Analysis

The graph of transient is shown below. This is a plot of the voltage across the capacitor (between node 2 and node 0), from time equals to zero to time equals to 100 nanoseconds. The time step (interval of time) is 1 nanosecond. The voltage function is a sine function defined by the voltage source (sin(0 1 10MEG)).

Diagram of Simulation for Part III. Tran Analysis

TIME        V(2,0)

(*)----------   -2.0000E-05   0.0000E+00   2.0000E-05   4.0000E-05   6.0000E-05

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

0.000E+00  0.000E+00 .            *            .            .            .

1.000E-09  3.464E-08 .            *            .            .            .

2.000E-09  1.381E-07 .            *            .            .            .

3.000E-09  3.028E-07 .            *            .            .            .

4.000E-09  5.242E-07 .            *            .            .            .

5.000E-09  7.985E-07 .            .*           .            .            .

6.000E-09  1.140E-06 .            .*           .            .            .

7.000E-09  1.532E-06 .            .*           .            .            .

8.000E-09  1.989E-06 .            .*           .            .            .

9.000E-09  2.492E-06 .            . *          .            .            .

1.000E-08  3.057E-06 .            . *          .            .            .

1.100E-08  3.664E-06 .            . *          .            .            .

1.200E-08  4.327E-06 .            .  *         .            .            .

1.300E-08  5.029E-06 .            .  *         .            .            .

1.400E-08  5.780E-06 .            .   *        .            .            .

1.500E-08  6.564E-06 .            .   *        .            .            .

1.600E-08  7.392E-06 .            .    *       .            .            .

1.700E-08  8.247E-06 .            .    *       .            .            .

1.800E-08  9.138E-06 .            .     *      .            .            .

1.900E-08  1.005E-05 .            .      *     .            .            .

2.000E-08  1.099E-05 .            .      *     .            .            .

2.100E-08  1.195E-05 .            .       *    .            .            .

2.200E-08  1.292E-05 .            .       *    .            .            .

2.300E-08  1.390E-05 .            .        *   .            .            .

2.400E-08  1.490E-05 .            .         *  .            .            .

2.500E-08  1.589E-05 .            .         *  .            .            .

2.600E-08  1.689E-05 .            .          * .            .            .

2.700E-08  1.788E-05 .            .           *.            .            .

2.800E-08  1.887E-05 .            .           *.            .            .

2.900E-08  1.984E-05 .            .            *            .            .

3.000E-08  2.080E-05 .            .            .*           .            .

3.100E-08  2.174E-05 .            .            .*           .            .

3.200E-08  2.265E-05 .            .            . *          .            .

3.300E-08  2.354E-05 .            .            . *          .            .

3.400E-08  2.440E-05 .            .            .  *         .            .

3.500E-08  2.522E-05 .            .            .  *         .            .

3.600E-08  2.601E-05 .            .            .   *        .            .

3.700E-08  2.676E-05 .            .            .   *        .            .

3.800E-08  2.746E-05 .            .            .    *       .            .

3.900E-08  2.812E-05 .            .            .    *       .            .

4.000E-08  2.873E-05 .            .            .     *      .            .

4.100E-08  2.930E-05 .            .            .     *      .            .

4.200E-08  2.980E-05 .            .            .     *      .            .

4.300E-08  3.026E-05 .            .            .      *     .            .

4.400E-08  3.065E-05 .            .            .      *     .            .

4.500E-08  3.099E-05 .            .            .      *     .            .

4.600E-08  3.126E-05 .            .            .      *     .            .

4.700E-08  3.149E-05 .            .            .      *     .            .

4.800E-08  3.164E-05 .            .            .       *    .            .

4.900E-08  3.174E-05 .            .            .       *    .            .

5.000E-08  3.176E-05 .            .            .       *    .            .

5.100E-08  3.174E-05 .            .            .       *    .            .

5.200E-08  3.164E-05 .            .            .       *    .            .

5.300E-08  3.149E-05 .            .            .      *     .            .

5.400E-08  3.126E-05 .            .            .      *     .            .

5.500E-08  3.099E-05 .            .            .      *     .            .

5.600E-08  3.065E-05 .            .            .      *     .            .

5.700E-08  3.026E-05 .            .            .      *     .            .

5.800E-08  2.980E-05 .            .            .     *      .            .

5.900E-08  2.930E-05 .            .            .     *      .            .

6.000E-08  2.873E-05 .            .            .     *      .            .

6.100E-08  2.812E-05 .            .            .    *       .            .

6.200E-08  2.746E-05 .            .            .    *       .            .

6.300E-08  2.676E-05 .            .            .   *        .            .

6.400E-08  2.601E-05 .            .            .   *        .            .

6.500E-08  2.522E-05 .            .            .  *         .            .

6.600E-08  2.440E-05 .            .            .  *         .            .

6.700E-08  2.354E-05 .            .            . *          .            .

6.800E-08  2.265E-05 .            .            . *          .            .

6.900E-08  2.174E-05 .            .            .*           .            .

7.000E-08  2.080E-05 .            .            .*           .            .

7.100E-08  1.984E-05 .            .            *            .            .

7.200E-08  1.887E-05 .            .           *.            .            .

7.300E-08  1.788E-05 .            .           *.            .            .

7.400E-08  1.689E-05 .            .          * .            .            .

7.500E-08  1.589E-05 .            .         *  .            .            .

7.600E-08  1.490E-05 .            .         *  .            .            .

7.700E-08  1.390E-05 .            .        *   .            .            .

7.800E-08  1.292E-05 .            .       *    .            .            .

7.900E-08  1.195E-05 .            .       *    .            .            .

8.000E-08  1.099E-05 .            .      *     .            .            .

8.100E-08  1.005E-05 .            .      *     .            .            .

8.200E-08  9.136E-06 .            .     *      .            .            .

8.300E-08  8.247E-06 .            .    *       .            .            .

8.400E-08  7.390E-06 .            .    *       .            .            .

8.500E-08  6.564E-06 .            .   *        .            .            .

8.600E-08  5.778E-06 .            .   *        .            .            .

8.700E-08  5.028E-06 .            .  *         .            .            .

8.800E-08  4.325E-06 .            .  *         .            .            .

8.900E-08  3.663E-06 .            . *          .            .            .

9.000E-08  3.055E-06 .            . *          .            .            .

9.100E-08  2.491E-06 .            . *          .            .            .

9.200E-08  1.987E-06 .            .*           .            .            .

9.300E-08  1.531E-06 .            .*           .            .            .

9.400E-08  1.138E-06 .            .*           .            .            .

9.500E-08  7.971E-07 .            .*           .            .            .

9.600E-08  5.225E-07 .            *            .            .            .

9.700E-08  3.013E-07 .            *            .            .            .

9.800E-08  1.492E-07 .            *            .            .            .

9.900E-08  4.364E-08 .            *            .            .            .

1.000E-07 -1.373E-09 .            *            .            .            .

- - - - - - - - - - - - - - - - - - - - - - - - - - -

D. What you can deduce

Part I. DC Circuit Analysis

From the observation in Part C, the linear drop of the voltage represents the linear voltage drop caused by resistors.

Part II. AC Circuit Analysis

From the observation in Part C, the voltage drop shows as the frequency increases, the voltage across the capacitor decreases. The decrease of the voltage is in a exponential form.

Part III. Tran Analysis

From the observation in Part C, the voltage of the capacitor increases and decreases according to the input voltage of the voltage source (V0).The voltage of the capacitor is observed by the transient plot, which is the voltage of the capacitor against time.