Instruction manual

HB 08-18-2010 7
20. CH2 VARIABLE/PULL control. Adjusts the vertically sensitivity of channel 2 contin-
uously.
21. CH2 INPUT JACK. Not needed in this lab.
22. CH2 AC-GND-DC switch. Not needed in this lab, but set at GND.
23. Horizontal TIME/DIV control. Adjusts the rate, in discreet steps, at which the electron
beam is swept across the screen. For the numbers to be valid, control 26 (VAR SWEEP)
must be in the CAL position. For example, if this control is set a 5 ms, the horizontal sweep
voltage will move the electron beam across the screen a distance of 1 cm in 5 ms if control
26 is in the CAL position (fully CW). Set this control for 1 ms.
26. VARIABLE SWEEP control. Provides for variable adjustment of horizontal sweep rate.
When this control is in the CAL position, control 23 is calibrated. Set in CAL position (fully
clockwise).
27. HORIZONTAL POSITION/PULL control. Adjusts the horizontal position of the trace.
Set pointer up. This control knob can be pulled out to expand the trace horizontally. Set
the knob in.
29. X-Y button. This button should be out. (button is “in” for x-y operation.)
30. HOLDOFF/PULL CHOP control. Check that this knob is in and full counterclockwise.
31. Trigger SOURCE switch. Selects the signal from which the trigger pulse is derived. Set
at CH 1 (CH=channel).
32. Trigger COUPLING switch. In the AUTO mode, a sweep voltage is generated and a
trace appears whether or not there is an appropriate signal for the scope to trigger on. In
the NORMAL mode, a trigger pulse and trace are only generated if the input voltage has a
value that satisfies the trigger voltage level chosen. With a strange scope it is often difficult
to find a trace. For this reason, set this control at AUTO.
33. TRIGger LEVEL/PULL(-)SLOPE. Adjusts the trigger level voltage, V
T
. Set knob
pointer up, which is approximately V
T
= 0. When knob is in, scope triggers on positive
slope of signal. When knob is out, scope triggers on negative slope of input signal. Set knob
in for positive slope triggering.
34. External Trigger. The connector at which an external trigger signal is fed into the scope.
Not used in this lab.
5 Using The BK Oscilloscope
In this section the BK scope is used to examine various AC voltages. You will be able
to “see” how the voltage depends on time, measure the amplitude at various times, and
measure times between different points on the voltage vs time curve. It will probably be