© D. Thiébaut 2003



To move it vertically, find the Vertical section, and turn the Position knob in the Probe 1 column. See how you an move the waveform up and down.
To change the vertical scale, locate the Volts/Div button in the Vertical section, and play with it. See how you can squeeze the waveform, or make it grow larger than the screen. Why would we want to make the waveform very large? Observe what happens to the top and bottom of the waveform at 200mV, 100mV and 50mV? What does this mean?
1 grid square = 100 µs
1 period = T = _______ squares = _________ µs
frequency = 1/T = 1 / _______ = ________ Hz
Let's now measure the voltages.
bottom to top of waveform = _________ squaresRecord the unit for vertical squares: ____ V/square, and calculate the peak-to-peak voltage (V p-p):
waveform height = _____ squares @ ____ V/square
= _____ Volts
Source +---- Time measurements ----+ clear Next
1 2 3 4 | Freq Period Duty Cy | Meas Menu
Period = _________ µs.How close is it to the one you measured?
Freq = ________ KHz
Duty cycle = _______%
Rise time <= ________ µs
V P-P = _____________ Volts
V avg = _____________ Volts
V Max = ________ Volts
V Min = ________ Volts
V Top = ________ Volts
V Base= ________ Volts
| Find everything there is to know (frequency, period, rise-time, voltage peak-to-peak, average voltage, top voltage, max voltage) about the 1 KHz clock signal on the digital kit. |
...
Note: it is very likely that the waveform will "jump" around as you move the cursor. That's okay. Move it until you can pin it down to the same transition the t1 cursor rests on.
t1 = _______ t2 = _______
Delta-t = _______ 1/Delta-t = ________
freq = _________ Hz
V p-p = __________ Volts
| Find everything there is to know (frequency, period, voltage peak-to-peak) about the signal present on Test Point #4 of the HP kit. |

Wire up a D-flip-flop ( SN74LS74) such that its Q-bar output is connected to its D input, and its clock input is connected to the Clock signal of the kit. Set this signal to 1 Hz (1 cycle per second). Also connect the clear and preset inputs to Vcc. Clear is an active low signal that sets the output Q to 0 when activated. Preset is an active low signal that sets the output Q to 1 when activated. Both clear and preset are typically signals used to initialize the flip-flop when the circuit is first powered up, or when it needs to be reset.
Connect both the Clock and Q signal to logic indicators.
Does this all seem familiar? What is the frequency at which the Q output oscillates? Find all there is to know about the Q output signal (as with the signals on the test board and the 1 Hz clock from above) and compare the answers to what you found about the 1 Hz clock signal earlier.
High frequency oscillations
Set the frequency of the Kit's clock signal to 100 Khz. Connect the probes of the oscilloscope to clock and Q (which should still be connected to the logic indicators). Observe the two signals with the scope. Is the relationship between clock and Q still the same? Looking at the scope and at the logic indicators, do you see there the answer to a question from a previous lab where you were asked to comment on the intensity of the logic indicator when the clock signal was beating at a rate of 100 KHz? Refine your explanations
What is the duty cycle of the clock signal (amount of time it is high divided by a period)? Of the Q output? (Hints: use the scope to tell you the answer!)