Oscilloscopes and Function Generators for John Deere Program

Prepared by Charles S. Tritt, Ph.D.
November 2, 1999

Equipment (for each pair of students working together)

Bench top power supply and oscilloscope.

Introduction

In this exercise you will use an oscilloscope to view the signal produced by a function generator. You will also set the function generator to produce a typical TTL level clock signal.

Safety Considerations

Dangerous line voltages are present at the outlets on your work bench. Do not insert anything other than approved power plugs into these outlets.

The voltages used in this experiments are low and relatively safe. However, do not intentionally make yourself part of your circuits.

Procedures

Connect the HP function generator high level output to the Tektronix oscilloscope Channel 1 input. Set the function generator dial to 10, 1 k Range, sine wave output, 0 DC Offset and set the Output Level knob to about half scale.

Set the oscilloscope Vertical Mode to CH1, Alt, set channel 1 to 5 volts/div, AC coupling, set the horizontal mode to A, 50 µ S/div, set the A trigger to Auto, positive slope, Ch1, Int Source and AC coupling.

Turn on both instruments. A sine wave should be displayed on the oscilloscope screen. Switch the oscilloscope channel 1 coupling to Gnd (ground) and use the channel 1 vertical position knob to move the line to the middle of the screen. Return channel 1 to AC coupling. Confirm that the function generator is producing a signal with the expected frequency.

Adjust the function generator Output Level knob to produce a 10 V peak-to-peak signal. Select the Sq (square) and Tri (triangle) Functions on the function generator and compare the displayed wave forms to the sine wave and to each other.

Select the Sq (square) function on the function generator. Reduce the output level to a 5 V peak-to-peak signal. Switch the DC Offset to + and adjust the offset to produce a 0 to 5 V output. This is a typical TTL clock signal.

Turn off both instruments and disconnect the function generator output from the oscilloscope.