Question

gow does scan expansion mesh and scan expansion meshless work in a oscilliscope?
in other words what happens inside an oscilliscope when i turn the time/div knob?

Answer 1

The “Time/Div.” Knob determines, how long the electronic beam that draws the curve takes for moving from the left to the right edge of a division. The knob controls the “time scale”. A “division” is one square on the screen of the oscilloscope.

For example, if the knob is set to “1 ms”, 1 ms passes until the beam moves through the division horizontally, i.e. it needs 10 ms for moving the beam from the left to the right edge of the screen because the surface is divided into 10 divisions.

When time base is on, a voltage is applied to the X-plate.
Timebase controls the speed at which the electron beam sweeps across the screen from left to right horizontally, then jump back to the left plate and the sweeping repeats. This is done by altering the frequency of the time base.

In short, when we change the Time/Division knob it changes the voltage of X-plate and according to this the frequency of the signal changes.