Grading
- Enhance thinking maturity
- Learn how to experiment/problem solve
- teamwork/communication/lab notebook
- Prelabs - 20% - do these before class (1B due next week)
- Lab reports - 30% done in class, collected at end of class
- Lab notebooks - 10%- checked periodically
- Teamwork - 10%
- Final Exam - 30% - lab, done individually
Basic problem: reduce cost of baking appliance
Experiment 1A:
Establish procedure for testing accuracy of thermistors
Voltage divider with resistors
Experiment 1B:
Compare accuracy of thermistors.
Voltage
divider with resistor & thermistor
Laboratory Notebook
What to write in notebook:
Reports and prelabs NOT included in notebook!
- List of equipment and supplies used
- Circuit and wiring diagrams
- Description of Observations / Results
- Instrument settings
- Source of errors
- Description of what you learned
- Questions / Suggested improvements in the experiment
Example Procedure (pg 152)
- Draw schematic and wiring diagram
- Develop voltage divider equation
- Use multimeter to measure resistor values
- Compared measured and nominal R values
- Measure power supply voltage
- Wire voltage divider circuit
- Measure Vs and Va on wired circuit
- Compare measured Va and predicted Va
- Report errors in Va from R and Vs.
Digital Multimeter - DMM - Ref pg 130DC Power Supply:
- only accurate for DC signals (direct current)
- Remove resistor from circuit to measure R
Proto-board: Used to connect electrical parts together
- +5V = red wire
- ground = black wire
- Color code wires (red = +, black = ground)
- Top row = + signal, bottom row = ground
- Use short wires to minimize noise
Lab 1B - (Next week)
- Voltage divider with resistor and thermistor
- Resistance of thermistor varies with temperature
- Calculate resistance of thermistor from output voltage
- Calculate temperature from thermistor
- compare two different thermistors, decide which is more accurate