PH4380 Computers in the Physics Laboratory ... (0,0,5) f ... 2 Cr

Prerequisite: PH2230 or permission of instructor.

Lab Fee: $100

Grades are based on laboratory reports only. Though labs are done in groups, each person needs to write their own report.

Equipment:

Intelligent instruments:
1.Philips counter GPIB.
2.AD/DA PCLAB11.
3.AD/DA National Instruments
4.Stepping Motor Controller with Indexer
5.Multimeter GPIB (Philips \& Keth.).
6.Phase Sensitive Detector (SRS) GPIB.
7.Digital Oscilloscope (Philips).



Computer:
1. Pentium motherboard.
2. Intel, 75~MHz AMD (P5), Cyrix 100 MHz.
3. CD-ROM, memory, HD 300Meg, 1.44 floppy, Video.

Experiments

From parts provided bulid the IBM compatible personal computer running DOS 6.0 and Windows 3.1 operational system. Install your copy of Labview windows.

Recommended literature: MTU library, Internet: www.motherboard.org and all sites of manufacturers of our equipment.

Experiment: #2 The thermistor Bridge

A thermistor in a Wheatstone bridge circuit is often used to detect small changes in temperature (smaller than 10 ^-4). Small temperature variation produce changes in the output voltage of the bridge which can be measured with the galvanometer (a very sensitive meter). However, using galvanometer has few drawbacks:

1. fluctuating thermal variations within the bridge and connecting leads contribute to voltage error.

2. drift within the DC amplifier contributes additional error voltages.

3. there are problems matching the low input impedance of the galvanometer with the bridge.

Therefore we use and AC method and Phase Sensitive Detector (PSD). Issuses related to temp measurements using AC method and recording its time transients:

1. Choice of reference frequency.

2. Choice of resitors in the bridge.

3. Communication with the PSD; you have a choice of IEEE-488 (GPIB) protocol or RS232 (serial port).

Once you complete your computerized temperature probe you can use it as a lie detector or anything else, I will make few suggestions.

Suggested literature:

1. Instruction manual for PSD.
2. GPIB protocol (LabView manual)
3. Any electronic Text (MTU library)
.

Experiment: #3 Emission Spectrum of Light Emitting Diode (LED)

Measure emission spectrum of green and red LED's. Fit experimental results to model function.

Suggested literature:

1. Principle of operation of grating spectrometer (MTU library)
2. Stepping Motor Controller manual.
3. Analog to Digital Converter (PC ISA board).
4. LED design and principle of operation (MTU library).

Experiment: #4 Arbitrary Function Generator

Your own design.

Experiment: #5 Emission Time Transients of automotive spark

Your own design.

Course Rationale:
There is no avoiding computers in the modern experimental laboratory. This course provides a hands-on experience using computers, computer interfacing techniques, and the design of physics experiments using computers as part of the instrumentation. This course is offered as an elective for students who are interesting in continuing with experimental work in the future.