1.To become familiar with the construction and use of the oscilloscope. 2.To gain experience in making simple measurements using this equipment. Materials and Equipment Needed:
Dual Trace Oscilloscope with probes
Please read this experiment carefully so when you come to the lab you understand some of the basic ideas of an oscilloscope. Become familiar with the documentation for this experiment and the location of the various buttons and knobs on the oscilloscope. Throughout this lab there are capitalized words and abbreviations which refer to the controls (knobs, buttons, dials, ect.) on the instrument. Upon completion of this lab the student will be able to:
1. Use an oscilloscope and manipulate the controls to display various signals.
2. Measure the frequency, period, and amplitude of a signal with the aid of an oscilloscope.
The oscilloscope is one of the most useful tools in electronics. Unlike simple meters, the oscilloscope provides a visual picture of the waveform being investigated from which measurements of amplitude frequency, phase, ect. can be made. The scope displays an accurate reproduction of the waveform being analyzed by causing an electron beam to draw a graph on the inside of a phosphor coated screen. The waveform stands still because the graph is drawn repeatedly and because of the persistence of the phosphors and the human eye. The vertical axis of the screen is calibrated in volts and the horizontal axis is calibrated in units of time. The word oscilloscope comes from the words “oscillo” short for oscillation and “scope” a Greek word for an “instrument for viewing.” There are a number of different types of scopes however most modern scopes are digital. This means that the input signals are first sampled and converted to a digital format. An onboard microprocessor can then be used to perform the desired manipulations on the signal. The onboard processor allows many measurements to be made automatically which previously required operator experience. Oscilloscopes can measure signals in the Gigahertz (109) frequency range however the Tektronix TDS 340 Oscilloscopes used in this laboratory is limited to 100 Megahertz. The following material included in the introduction section of this experiment pertains to an older analog Tektronix oscilloscope however most of the basic concepts apply to the newer digital oscilloscopes. Read this material over completely before you come to the laboratory to perform the oscilloscope experiment Documenting the Scope Configuration:
The first part of this experiment involves documenting a saved user configuration. Power up the scope by pressing the ON/STBY switch in the extreme lower left hand corner of the front control panel. Wait for the monitor to power itself on and to finish testing. A standard configuration has been created for this scope. Push the SAVE/RECALL button in the upper center directly above the HORIZONTAL POSITION control knob. Select RECALL SAVED SETUP in the lower screen menu with the buttons below the screen and RECALL SETUP 1 USER in the right screen menu with the buttons to the right of the screen. Clear the menus from the screen by pushing the CLEAR MENU button located in the lower right hand side of the screen enclosure. Record information displayed across the top CRT Screen
Record the information displayed on the bottom of CRT screen for Channel 1.
Remove CH1 display with the WAVEFORM OFF button. Select Channel 2 using the CH2 button in the second vertical row of buttons left of the CRT screen. Record the information displayed on the bottom of the CRT screen for Channel 2.
Remove Channel 2 and reselect Channel 1. Push the VERTICAL MENU button in the VERTICAL section. Record the data on the bottom of the CRT screen beginning with “coupling.”
Select Channel 2 and record data on the bottom of CRT screen in the same format.