Using the Oscilloscope Front Panel
There are two adjustments for each channel:
Also, there is a trigger level adjustment to adjust the voltage level used in triggering the oscilloscope. To read more about using triggers and trigger modes, click here
Analog Gain Switches
The analog gain switches change the gain of analog stage of the oscilloscope. The hardware reports the current gain and the software adjusts for the reported gain. That is, a one volt peak-to-peak waveform on the channel input will always measure one volt peak-to-peak on the oscilloscope screen. In effect, you will change the gain and nothing will appear to happen on the screen. Therefore, the analog gain switches do not modify the amplitude gain of the waveform as displayed on the oscilloscope, but it does change the voltage resolution and the voltage range of the oscilloscope.
The oscilloscope uses an 8 bit ADC and scales a voltage over a range of 0 to 5 Volts. The gain of the analog gain stage can be increased so the sensitivity of the ADC is increased (the side effect of changing the analog gain is the range of measurement is decreased. The sensitivity is:
Vstep = 3.9 / Gain * 5 / 256 = 0.076 / Gain
And the range of measurement is:
Range = 5 * 3.9 / Gain = 19.5 / Gain
Vmax = + Range / 2
Vmin = - Range / 2
The 3.9 is the gain introduced by the analog stage with the gain switch selecting a gain of 1. Below is a summary of each gain setting, the sensitivity, maximum measurable voltage, minimum measurable voltage, and voltage range.
AC/DC Coupling Switches
The AC/DC Coupling Switches are on the front panel of the oscilloscope. The position of the coupling switch determines whether or not the waveform is placed in series with a capacitor. If the coupling is set to DC then the signal is not placed in series with a capacitor and the DC component of the signal is preserved. If the coupling is set to AC then the signal is placed in series with a capacitor and the DC component of the signal is removed.