A signal or function generator is a device that can produce various patterns of voltage at a variety of frequencies and amplitudes. A common use is to test the response of circuits to a known input signal. Most function generators allow you to generate sine, square or triangular AC function signals. You can view the signals produced by connecting the signal generator, using a BNC-Banana adapter, to an oscilloscope.
Use the amplitude control to vary the voltage difference between the peaks and the troughs of the output signal. The freqeuncy control varies the rate at which the signal oscillates. You need to first select a broad range of freqeuncies using the buttons on the left, and then select the frequency more precisely using the dial.
Examples of sine, square, triangular and sawtooth waves are shown in figure 2.