Bin Contents: Resistor & Capacitor Set 1 (Green Label), Resistor & Capacitor Set 2 (Orange Label), a dongle for the Oscilloscope, a pack of Wires, and a Digital Multi Meter (DMM).

NOTE: Be careful with the wires! Never pull by from the cord! Always pull from the plug!

Also – re-tie the wires as indicated! 

Obtain a Gray LVPS (Low Voltage Power Supply) – return it when finished.

Obtain an Oscilloscope and Power Cord – return when finished.

Note: The Oscilloscope’s Power Cord requires a Gray AC Prong Adapter!

Obtain an AC / Function Generator and Power Cord – return when finished.

Note: If your table doesn’t have an LCR Meter, take it from the cart’s middle shelf.

The Resistor and Capacitor used for Part A.

The Resistor and Capacitors used for Part C.

Setup an LCR Meter for measurement; for this experiment, the LCR Meter measures Resistance and Capacitance only!

Press the L/C/R button to cycle through the modes; here the meter is set to Resistance (MOhm is displayed on the right side).

Press the L/C/R button to cycle through the modes; here the meter is set to Capacitance (nF is displayed on the right side).

Measure the actual Resistance and Capacitance values for all your components.

Note: All Capacitors’ -/+ sides are labeled!

Measure the Resistance of the DMM itself (make sure the dial is set to Volts as indicated).

Build the initial circuit for Part A.

Note: The red wire is NOT connected to the LVPS!

Connect the volt meter directly across the capacitor; ensure the the -/+ polarity is maintained.

Note: The red wire is NOT connected to the LVPS!

Turn on the LVP; set its Current knob half-way and set its Voltage knob to a value slightly over 10 Volts.

Note: The red wire is NOT connected to the LVPS!

To charge up the capacitor, you only need to touch the metal end of the red wire into the red port of the LVPS; you should not connect it firmly so that it may be pulled away easily.

Simply touching the metal end of the red wire into the LVPS’s red post is enough to fully charge the capacitor.

Remove the red wire from the red port and voltage across the capacitor starts to drop – this is part of the experiment where you record the voltage every 30 seconds.

Touch the metal end of the red wire to the other side of the capacitor to instantly discharge it.

To build the final circuit for Part A, simply attach the Set 1 Resistor in parallel to the Set 1 Capacitor as shown.

Another view of Part A’s final circuit.

Charge the capacitor exactly as you did before.

Remove the red wire from the LVPS’s red post and record the voltage every 30 seconds exactly as you did before.

Because the AC power is poorly conditioned, the Oscilloscope requires the Gray AC Prong Adapter.

You will not be able to perform Parts B & C if the Oscilloscope’s power cord does not have that Gray AC Prong Adapter!

Try not to undo the velcro tying the AC / Function Generator’s power cord together – keep the table tidy!

For this experiment the dongle is connected to the X/1 port on the Oscilloscope.

Turn on the AC Generator / Function Generator, set its Frequency, Voltage, and Waveform to the values indicated by the manual.

Turn on the oscilloscope ….

… and connect the AC/Function Generator directly to the dongle; the Oscilloscope will not show you a good signal initially ….

Press the ‘AUTO’ button found at the upper, right side of the Oscilloscope.

‘AUTO’ will always clean up the display to give you the optimum view of the signal.

You can make your own adjustments and refinements to the display.

for the gray Vertical Area (left hand side):

Since we are only using the X/1 channel, only the button with ‘1’ is illuminated. The large knob (labeled  V – mV) on top of the illuminated ‘1’ button adjusts the vertical (voltage) scale factor, this causes the signal to appear taller or shorter depending on the scale value you set to. The small knob (labeled Position) below the illuminated ‘1’ button adjusts the vertical positioning of the signal; you don’t need to use this knob for today’s experiment.

for the gray Horizontal Area (right hand side):

To the right of the vertical (voltage) adjustment knobs is a similar set for the horizontal (time) adjustment knobs. Likewise, the large knob (labeled s – ns) controls the scale factor for the time axis (the horizontal axis), this causes the signal to widen or narrow depending on the scale value you set to; the small knob (labeled Position) adjusts the horizontal positioning of the signal – this moves the signal left or right – you will be using these knobs later.

Press the ‘Menu On/Off’ button to remove any menu from the screen.

The most important values on the screen are found in lower portion against the gray border.

Everything related to Channel X/1 is in yellow – Vpp is the signal’s peak to peak voltage (it’s displayed as 10.08 V in this example) – CH1=2.00V is the vertical scale factor for Channel X/1.

Everything related to Channel Y/2 is in violet – we’re not using Channel Y/2 so nothing of value appears except Vpp=****

Everything related to time appears in white; M 100us is the horizontal or time scale value – MPOS is of no practical concern for this experiment.

Other values may appear along this lower part of the display and elsewhere but for now only the concepts listed above are important to the experiment.

Build the circuit for Part C; ensure that the Capacitor’s polarity matches the way it is connected to the AC/Function Generator!

Connect the Capacitor to the Oscilloscope as indicated, note, again that the polarity needs to match.

The signal; you may need to adjust the horizontal / time scale knob as well as horizontal / time position knob the get your signal to match what’s shown; variances are permitted.

Press the ‘Cursors’ button (it becomes illuminated when you do); you may also want to press the ‘Run/Stop’ button to freeze the display (it will turn red).

Pressing the ‘Cursors’ button brings up the CURSOR menu; press the white button next to mode until ‘Manual’ is selected.

Ensure that type is set to Time and that Source is set to CH1 (press the buttons next to the settings to change them, if needed).

This appears on the upper left part of the display when the CURSOR is activated; for this experiment, delta-T at the top is the important value.

The Intensity/Adjust knob, at the upper left, is activated & illuminated when the CURSOR is activated; use this knob to move the cursors around the display.

Press the button next to the Cur A setting and use the Intensity/Adjust knob to move Cursor A (it’s the brighter vertical line at the left) so that it hits the peak of the signal.

Press the button next to the Cur B setting and use the Intensity/Adjust knob to move Cursor B (it’s the brighter vertical line at the right) so that it hits the intersection of the signal and the V = 0 Line (the V = 0 Line is the main horizontal axis of the display).

The value of delta-T is the T-1/2 you’re looking for; it’s the time it takes for the signal to decay from the location of Cursor A to the location of Cursor B (that is, when the voltage decreases to 1/2 its original, peak value).

Swap the capacitors ….

… to redo the measurement.

The signal will not be correct when the capacitor is swapped.

Therefore adjust the frequency until you obverse the required pattern; you may need to press ‘AUTO’ repeatedly as you change the frequency.