Eric R Snow wrote:

Thanks all for the info so far. Now another one. The probe is set at
1X. The volts/div is set at 50 m. the time/div is set at .1 ms. So
this tells me that each vertical division is 50 millivolts and each
horizontal division is .1 milliseconds. The probe is clipped to the
calibration bar. This bar is labeled as 300 mV 30mA ~1KHz. The display
shows the square wave with 6 divisions vertical and just over 10
divisions horizontal. Using the VAR knob in the center of the time/div
knob I can adjust the display to show exactly 10 divisions. When this
is done is the display correct? Or is it the calibration bar that is
wrong?
Thanks,
Eric

The var knob should be turned full clockwise for the vertical scale to
be correct. Tektronic scopes have a detent when the var is turned full
clockwise. It seems to be correct from the numbers you gave. If you
assume that the calibration voltage is right, 300 mv., and your
sensitivity is set for 50 mv per division, 300 mv will deflect the
display six divisions.

John