Oscilloscopes HP 54600B Digital Oscilloscope Alex Jones COE 0501

Safety Tips Protect Yourself: Avoid contact with Voltage or Current Sources • Use shrouded test leads and alligator clips. Leads: Connect to oscilloscope first; Connect/disconnect at source so loose lead is dead. Connect probe to ground before connecting to high. Protect the Scope: 400V maximum on input. Use probes to reduce high voltages. Be familiar with user’s guide.

Oscilloscopes Oscilloscopes display the relationship of Voltage vs. Time waveforms for analog and digital signals. The display is like a dynamic plot. Therefore we must be able to adjust the scales and offsets of the “plot” of the waveform. Voltage - set the Input / vertical scale factor Time- set the horizontal / time scale factor Position (Vertical and Horizontal) Triggering - when should it start to draw? Storage - keep a copy Measurement - measure features of the waveform

Front Panel Features Measurement Save/Recall Cursors Storage Horizontal Position Measurement Save/Recall Cursors Storage Autoscale/ Display/Print Triggering Vertical Scale Vertical Position Inputs External Trigger Intensity Calibration Ground Power Horizontal Scale What’s wrong with this picture?

Task - Front Panel Draw a picture in your lab notebook of the front panel of your scope. Every button, knob, and connector should be depicted and labeled. Use an entire page of your lab notebook for this.

Task - Front Panel On the next page of your notebook, make a list of the buttons, knobs, and connectors on the front panel. As you learn about each item in the list, write a brief description of it in your notebook.

Power Switch • This switch turns the oscilloscope on and off.

Intensity Knob • This knob adjusts the brightness of the display If no trace is seen, it may be because the intensity knob is set too low.

Ground Connection • This connection may be used to ground probes.

Signal Inputs • These connections are used to connect coaxial cable, probes, etc. to the oscilloscope. The outside of the connector is grounded.

Connecting a Signal £ • Make sure the input voltage level 400 V. Connect a BNC cable or a probe to a channel input. Connect the other end of the cable or probe to the device to be measured. £

Task - Calibration Signal Connect a probe to channel 1. Connect the red lead to the calibration signal below the display. Push the Auto-scale button. Draw a picture of the resulting waveform in your lab notebook.

Vertical Section addition menu volts per division volts per division channel menu channel menu position knob position knob

Input Selection Use the push buttons to enable/disable each channel. These also enable the “soft keys” under the display

DC vs. AC Coupling For digital signals we almost always want DC coupling. AC coupling centers the signal on 0v Digital signals swing between 0v and 5v D V

Vertical Scale • Use the vertical volts/div knobs (located above the channel input connector) to scale the signal vertically on the screen.

Task - Calibration Signal Adjust the volts/div knob so that the entire calibration waveform is visible on the screen, and appears as large as possible. Record the volts/div setting in your lab notebook. Use the scope to measure the amplitude of the calibration waveform.

Vertical Positioning • Use the vertical position knob (located above the channel input connector) to position the signal vertically on the screen.

Horizontal Section delay knob main/delayed menu time per division

Time Base • Turn the time/div knob to adjust the sweep speed (time base). The sweep speed has a range from 2ns to 5s.

Task - Calibration Signal Adjust the time/div knob so that one period of the calibration waveform is visible. Record all time base parameters in your lab notebook. Use the scope to measure the period of the calibration waveform. Compute the frequency of the waveform.

Horizontal Positioning • Use the delay knob to move the signal horizontally. Note the value displayed on the status line.

Trigger Section source menu trigger level knob mode menu slope/coupling menu holdoff knob

Triggering Source Menu • Use this menu to assign a trigger source. The choices are line, CH1, CH2 and external.

Triggering Mode Menu • Use this menu to choose a trigger mode. The choices are auto level, auto, normal, single, and TV.

Triggering • Use the level knob to set the trigger voltage. The screen will display the trigger level in inverse video and a horizontal line representing the trigger location.

Triggering 1 Triggering level + Slope - Delay

Custom Features Autoscale Voltage menu Time menu Cursor menu Storage Delay

Custom features setup menu time menu voltage menu cursor menu trace menu cursor knob display menu autoscale print/utility

Auto Scale £ • Sets the Time Scale and Vertical Scale for all inputs Uses the highest active channel (1,2,3,4, ext) as trigger £

Voltage Menu • Use this menu to make automatic voltage measurements. Measurements include peak to peak voltage, rms voltage, max voltage, etc. The choice is made using the softkeys below the display.

Voltage Readings Vrms = 0.707 Vp (Sine wave) Vpp Vrms Vp time

Time Menu • Use this menu to measure frequency, period, duty cycle, risetime, etc.

Frequency and Period Period ( ) t T f = 1 Hz rad/s time w p × 2

Cursor Menu • This menu brings up a list of cursor commands and activates the cursor knob. The cursors can be used to measure specific voltages, times, etc.

Storage These buttons control the storage features of the scope. Run, Stop, Auto-store, Erase Save, Recall

Storage Save/Recall Run - Normal operation Stop - Keep the most recent trace, do not overwrite Auto-Store - Keep overwriting traces, with dim lines Erase - Erase all traces Save/Recall Trace - Can store 2 “screen dumps.” Brings up soft keys Settings - Can store scope settings for reuse

Delay This button enables the use of two time-bases for the same signal This gives the ability to have a global and zoomed picture of the waveform at the same time. It enables a soft key menu (XY, Vernier, Time Ref)

Storage Save/Recall Run - Normal operation Stop - Keep the most recent trace, do not overwrite Auto-Store - Keep overwriting traces, with dim lines Erase - Erase all traces Save/Recall Trace - Can store 2 “screen dumps.” Brings up soft keys Settings - Can store scope settings for reuse

End of Scope Presentation