An Investigation of Ohm’s Law General Instructions The assessment for the part of Electrical and Electronic Engineering is based on this simulation lab. Hand in your individual lab report before the...

An Investigation of Ohm’s LawGeneral InstructionsThe assessment for the part of Electrical and Electronic Engineering is based on this simulation lab. Hand in your individual lab report before the published deadline via BB.Objectives:

1. To know how to use the measurement.


2. To measure the voltage/current relationship of two electrical devices and hence to investigate the application of Ohm’s Law


3. To understand the total resistance of resistors connected in series (or in parallel)

Ohm’s Law
states that the current, I, flowing through a resistor of resistance R is related to the voltage V across the resistor by the equation:
V = IR
Practical and theoretical workTask 1) Use Ammeter to measure current and Voltmeter to measure voltage across


Sheffield Hallam UniversitySchool of Engineering Chemical Engineering Practice - Electrical and Electronic Engineering Lab An Investigation of Ohm’s Law General Instructions The assessment for the part of Electrical and Electronic Engineering is based on this simulation lab. Hand in your individual lab report before the published deadline via BB. Objectives: a. To know how to use the measurement. b. To measure the voltage/current relationship of two electrical devices and hence to investigate the application of Ohm’s Law c. To understand the total resistance of resistors connected in series (or in parallel) Ohm’s Law states that the current, I, flowing through a resistor of resistance R is related to the voltage V across the resistor by the equation: V = IR V DMM d.c. power supply A DMM R C black, - , common ground, 0V red, + I Practical and theoretical work Task 1) Use Ammeter to measure current and Voltmeter to measure voltage across the resistor. Wire up the circuit shown above using the 24( resistor. Task 2) For values of V from 0 to 5V with steps of 0.5V, measure the corresponding values of current and enter them in a table of results (with 3 decimal places). Enter the value of resistance calculated for each set of readings. Task 3) Plot a graph of voltage V (as the y-axis) against current I (as the x-axis). From your graph: · How can you find the resistance, R ? · Does R change ? · How accurate might your results be ? Task 4) Now repeat Parts 1) to 3) with the 12V, 12W filament lamp replacing the resistor, plotting the new graphs and answering the questions of Task 3 again (use the same graph paper if possible). Task 5) Connect two resistors of 24( in series, and in parallel and measure the equivalent resistance by ohm's law (VT/IT, add a voltage source to provide VT) Task 6) Construct the circuit as below, and use Ammeter and Voltmeter to find out the current and voltage for the resistor with 2(. Record all results and notes obtained, plotting graphs as you work, so that mistakes show up before you dismantle circuits! Ensure as far as possible that such notes will allow you to work on collected data at a later stage if required. Please use clear labels for graphs, tables etc. Measurements for Task 2 V I (specify units) R (specify units) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Observations: Measurements for Task 4 V I (specify units) R (specify units) t1 0.5 t2 1 t3 1.5 t4 2 t5 2.5 t6 3 t7 3.5 t8 4 t9 4.5 t10 5 Observations: The Lab Report The lab report for this assignment should be semi-formal in style. It should be prepared with a word processor. It should include the followings elements: 1. The Title Page. This must show the report title, author, module title 2. Introduction. One paragraph summary of the report, including a brief but clear summary of the lab and objectives. 3. Experimental results and discussions. 4. Conclusion. It should summarize the data, calculated results and the main finding. Marking Scheme Presentation of Report (format, number of words etc) (10%) Contents of the Report, (technical content) (90%) >=70% 60-69% 50-59% 40-49% Fail Introduction and conclusion 10% Well written and discusses the context of the experiment. There is discussion about why and how the experiment will be conducted A brief theoretical background is discussed Conclusions" contain brief summary of points raised in discussions. Introduction is well written and discusses the context of the experiment. There is discussion about why and how the experiment will be conducted. A brief theoretical background is discussed. Conclusions contain brief summary of points raised in the discussion. The introduction is well written and lists the aims and objectives of the experiment. Aims and objectives may be poorly defined or not quantitative. There is little or no context provided and limited theoretical background Conclusions are given, but either do not correctly summarise points in the discussion or include new information. A brief introduction is given but fails to provide information relating to context or aims/objectives of the experiment. The introductory sections may be confused with procedure or other sections. Conclusions are not attempted. Little or no introduction is given. Material sourced for the introduction is taken largely from the laboratory sheet. Conclusions are not given. VH H M L H M L H M L H M L H M L VL Results and discussions for all Tasks 80% Data presented in a logical manner using the most appropriate methods. Data is presented in a style that clearly displays the points being referred to in the text. Observation of results is given showing good understanding. Discussion displays solid understanding of the physics of the experiment. Points raised about results relate back to the aims and objectives in the introduction section. Errors in the experiment have been identified and an attempt made to quantify and/or explain them. "Repeatability is discussed. Data is presented in a suitable manner. It may be displayed so it cannot be compared with other results or so trends cannot be seen. Observation of results is given but shows limited understanding of the experiment. Discussion displays good understanding of the physics of the experiment. Points raised about results relate back to the aims and objectives in the introduction. Errors in the experiment have been identified and an attempt has been made to indicate their impact on the results. The data presentation method is not appropriate. Raw data may not be (properly) processed or there is limited discussion of how raw data has been converted into experimental results. Discussion displays some understanding of the physics of the experiment. The points raised in the discussion do not relate to the aims and objectives set out in the introduction. Errors in the experiment are listed and qualitatively discussed. Raw data is presented without processing or calculations being shown. Very little discussion of results or the discussion is limited to basic description with little context. Discussion displays limited understanding of the physics of the experiment. Results are not discussed or with little understanding or reference to why the experiment was conducted. Errors are listed only, without attempt to suggest importance. Little or no has been presented. The data presented "may consist of a table of raw data or a graph" that is not discussed. No points are raised in the text to illustrate why data is displayed. The discussion illustrates that student has little or no understanding of the experiment or the physics of the system. Presented results not discussed, or discussion is a reiteration of the results presented. There is little indication that experimental errors have been considered VH H M L H M L H M L H M L H M L VL Presentation (10%) Professionally presented (including the graphs). All standards in marking proforma adhered to. Graph and tables are well numbered and captioned. Use of English is concise, technically correct and precise. Clear and consistent referencing is used. Document is well presented (including the graphs). One or two standards in marking proforma not adhered to. Graph and tables are well numbered and captioned. Use of English is technically correct. Clear and consistent referencing is used. Document is well presented (including the graphs) but a few minor standards in the marking proforma are not adhered to. Graph and tables are numbered and captioned. The standard of English is reasonable, but the use of colloquial terms or journalistic styles is present. The document is well presented (including the graphs), but fails to conform to many standards in the marking proforma. Graph and tables are poorly numbered and captioned. Poor use of English. Sourced material is referenced, but not consistent or lacks enough detail. Document is poorly presented or hand-written (including the graphs). Many of the important standards in the proforma not adhered to. Graph and tables are not numbered and captioned. Standard of English is poor. Sourced material is not cited VH H M L H M L H M L H M L H M L VL 3 _1285680837.doc DMM A d.c. power supply DMM V RC black, -, common ground, 0V red, + I