Vertical amplifier section

Position Controls vertical positioning of oscilloscope display.
Sensitivity Selects the sensitivity of the vertical amplifier in calibrated steps.
Variable Sensitivity Provides a continuous range of sensitivities between the calibrated steps. Normally the sensitivity is calibrated only when the variable knob is in the fully clockwise position.
AC DC GND Selects desired coupling ac or dc for incoming signal applied to vertical amplifier, or grounds the amplifier input. Selecting dc couples the input directly to the amplifier; selecting ac send the signal through a capacitor before going to the amplifier thus blocking any constant component.