Op-Amps II

Op Amps II

Purpose: To observe the effects varying the feedback and input resistances in an op amp circuit.

In order to determine what resistors to use calculations were performed to obtain a gain of 10 and 0.1mA current.

 The circuit was then built and Vs was adjusted to 0.25 V using a voltage divider as shown.

A 1kΩ resistor was then  placed as the load.

Voltages were then recorded across all resistors using this set-up.

The following data was obtained

For V_IN = 1V 

       Measured I_cc = 0.867 mA 

                Calculated P_cc = 12*0.867 mP = 10.404 mP

       Measured I_ee = -0.979 mA 

                 Calculated P_ee = 12*0.979 mP = 11.748 mP

       I_cc + I_ee = 0.112 mA

       The percent error is 12% therefore, it is consistent with KCL.

  For V_IN = 1V 

    Measured I_cc = 0.877 mA 

            Calculated P_cc = 12*0.877 mP = 10.524 mP

    Measured I_ee = -0.984 mA 

             Calculated P_ee = 12*0.984 mP = 11.808 mP

     I_cc + I_ee = 0.107 mA

     The percent error is 07% therefore, it is consistent with KCL

Finally,  With percent errors of 12% and 7% this experiment is considered a success and obeys Kirchhoff's Current Law. We saw that the gain depends directly on Rf/Ri.

Op-Amp Lab (incomplete)

Gain of 10

Thev lab

Thevenin Equivalents

Purpose: To find the Thevinin equivalent circuit and verify it experimentally.

Experiment:

The initial circuit as well as the calculations and transformations used to find the thevenin equivalent circuit as well as practical values used in the experiment.
We also calculate the smallest acceptable R_L2 that will give a minimum load of 8V.


We build the simple circuit using the equivalents and take the voltage and resistances.



We then build the original circuit and get the data.






Data:


As it is seen the values did match up showing that the thevinin equivalents worked.

PSpice

Pspice

Problem 1

Problem 2

Circuit from problem 2

Graph from Problem 2

Max. Power = 7.4955W at RL = 3.5106 Ohms.

Lab 6- Maximum Power Transfer

Purpose:

To find the maximum power of a circuit through 2 methods.

Procedure:

For this lab this circuit was set up.

Using DMM's the resistance and voltage was measured in the circuit as the the Potentiometer was adjusted in order to determine at which resistance maximum power occurs.

These values and graphs were obtained.

Based on this graph maximum power occurs at 1136Ω.

this experiment was also performed using logger pro. However it is difficult to analyze this data for maximum but a trend is visible.

Freemat lab

Purpose: 

to explore freemat and its applications applicable to this course.

              Display of sine graph

             Display of sine and cosine graphs.

Examples:
1)
:V1 = 15V, V2 = 7V, R1 = 20Ω, R2 = 5Ω, and R3 = 10Ω

Setting the information into matrix form we get-->

The current found through R3 is -0.1857A




2)
Circuit 1 has a time constant of 100 ms and circuit 2 has a time constant of 200ms. The output is 2e^(-t/ τ) where τ is the time constant. Using graphs, identify which circuit will have the lower output sooner.

Circuit A will have a lower output.

comparing the curves of 2e^(-t/tau) and 2(1-e^(-t/tau)):

3)

Determining the output of adding the sinusoids: 3sin(2t+10) and 5cos(2t-30)

The function and their sum.

When we change the frequency to 10Hz we have:

This shows that changing the frequency changes the period.

Lab 5 - Transistor Switching

Transistor Switching

Purpose:

The purpose of this lab is to observe the effects of a transistor in a circuit.

Procedure:

In the first part of this experiment this circuit was set up.

in place of a push button we used our fingers to show that the create enough of a voltage difference to switch the transistor as seen here.

Circuit 1

After setting up that circuit circuit two was set up.

Circuit 2 

Circuit 2

This circuit was set up with a potentiometer in in order to adjust the voltage at the base of the transistor in order to to create a graph to determine it's gain.

Circuit 2

Current was measured ate the base(A1) and exiting the emitter(A2).

These values and resulting graph were obtained.

Based on the graph the beta gain of the transistor is 136.02  if you ignore the points after saturation  which occurs at about 0.2 to 0.4 amps.