Mini-Module: Function Generator
There is a function generator built into the trainer module / breadboard which we will use
as a primary tool in the analog and digital part of this class. This generator produces a
variable amplitude, variable frequency waveform which can be a triangle, square, or sine
(sort of) wave pattern. As mentioned in the oscilloscope mini- module, figuring out the
function generator and how it works is easier with the scope in place. (Actually, the
scope claims it’s easier the other way, but the point is, its best to dink around with both a
bit at the same time.)
Setup
Choose the triangle waveform and set the other dials to the center of their ranges. Hook
up the output of the function generator to the scope on one channel. Set the scope to
trigger off this channel and play with the trigger level until good reproducible triggers are
seen. Then use the timebase and the output level of the scope to get a good picture of the
waveform.
Characterizing the Function Generator
Try changing the type of waveform to see what each type looks like. The knobs are kind
of weird on these units; they don’t always point where they should. You can tell by
inference where they are pointing by running the whole range. Put the triangle wave
back on. Next try the fine frequency knob and observe the change. How would you
measure the frequency of the waveform? Try the coarse frequency knob and note the
changes. Center the waveform vertically on the display and try changing the amplitude
of the waveform. (Beware, you may lose triggering in this step or the next.) Finally try
changing the offset of the waveform. If it doesn’t look like the waveform is moving up
and down, check to see if the scope is on DC or AC. It needs to be on DC to see these
changes. How would you measure the offset voltage of the waveform? How about the
peak to peak amplitude? You will become familiar with the operation of the function
generator by the end of this class.