DEPARTMENT OF ELECTRICAL ENGINEERING
ESE UNDERGRADUATE LABORATORY
ESE 205: Electrical Circuits and Systems I Laboratory
Lab: 1
Introduction to the Lab – orientation, policies and
safety
Objective:
1. Selection of partners (two per group)
2. Review lab procedures, safety issues, grading policies.
3. Introduction to a typical work bench and the instruments
4. Familiarization with Multisim
5. Introduction to the concept of transduction and transducers
5. Simple resistance measurements (using multimeter)
Pre-Lab Assignment:
Read the following handouts: (available on the homepage)
Do not print on the RCA printer.
- 1. General Laboratory Policies
- 2. Good Laboratory Practice and Lab Safety
- 3. Grading Policies
- 4. Guidelines for keeping the Lab Notebook
- 5. Guidelines for writing Lab Reports
- 6. Typical ESE lab workstation
- 7. Use of LM 34 Temperature sensor
- 8. Get a toolset (protoboard, wire stripper, long nose pliers and screw driver set).
In-lab Assignment
Before doing the exercise, review the section on "Safety" in "Electrical Laboratory Practice".
A. Equipment:
1. Chromel / Alumel wire
2. Digital multimeter (HP34401A)
3. LM34 temperature sensor
4. Protoboard
1. Grounding and safety
Assume that your little brother is working with his computer but does not find an outlet with three wires (with ground). He forces the three wire plug into a two wire receptacle (without ground connection)! Of course one should never do that, but your little brother hasn't taken any EE classes.
Your brother has just come from outside where he took a good swim in the pool. He is barefoot and not completely dry. Will your brother be in danger of a lethal electric shock if the hot (120V) wire accidentally touches the metal case of the computer? Assume that the resistance of the case is zero and that the resistance of the load in the computer is very large.
Figure 1: Schematic of brother circuit
The floor is damp and is a good conductor, the contact resistance of the skin is Rskin = 150 Ohms, the resistance of his arm and leg is each Rarm = Rleg = 100 Ohm, and his trunk Rtrunk = 200 Ohm.
Calculate the current that will flow through your little brother’s body. Is it a dangerous level?
Include a schematic of the circuit; calculation of the current; discussion of the results. Write neatly and presents your results in an organized manner.
2. Car
battery
Assume that your other brother is working on his car and touches the two poles of the car battery. The battery has a voltage of 12V and can deliver 100A for a short time. Will he be in danger or not? Calculate the current flowing through your brothers body (assume wet skin; use the same numbers for the resistances as in the previous example). Compare with the results of the previous problem. What would you conclude about the importance of voltage levels in addition to currents?
Figure 2: Schematic of brother with car battery
3. Using Multisim
Start Multisim on the PCs and draw the schematic of the circuit of the previous two problems. Simulate the circuit (use the current meter in Multisim) and compare the result with the one you calculated.
Include a printout of the circuit in Multisim and the result (one per group).
4. Using the digital multimeter
HP34401A
Use the
digital multimeter HP34401A to measure the contact resistance of you and
your partner. Repeat the measurements after making your skin wet and notice the
difference.
NOTE: The resistance measurements will be higher than the values mentioned in
the exercise 1. The one mentioned are AC values as compared to the DC values
measured here. Discuss your results briefly.
5.
Temperature sensor
Use LM34, temperature sensor to measure temperature :
http://www.national.com/ds/LM/LM34.pdf
Use LM34 to measure your body temperature using DMM !
Created by Jan Van der Spiegel:
Updated by Sid D on :