# Step 1

Construct the circuit in the diagram below, and connect channel 1 of the TBS1000B-EDU oscilloscope to node A and channel 2 to node B.
Channel 1 will measure the voltage Vx and channel 2 will measure the voltage drop on R2, which has the resistance equal to 1 Ohm. As we discussed in the theory section, we will use the voltage drop on R2 to give us the information of the current through the circuit, Ix, with a 1:1 conversion rate. For example if we measure 100mV, this represents Ix=100mA.
Here is an example of testbench setup:
and here is a detailed picture of the schematic implementation:

# Step 2

- Setup the power supply voltage to 5V.
- Setup the Oscilloscope Channel 1 Input to DC mode, Vertical scale =1V/div, and Channel 2 input to DC mode, Vertical scale = 20mV/div.
- Setup the Oscilloscope time base to 500ns/div (this is not important here since we measure DC voltages that do not change in time and are represented as horizontal lines on the display)
- Setup the Oscilloscope Trigger to Auto mode.
- Alternately press the "Autoset" button and make the adjustments to settings after the oscilloscope displays the waveforms.
- With this setup the oscilloscope screen should display two horizontal lines representing the voltages at nodes A and B of the circuit, as shown in the picture below:

- Press the "Math" button on the oscilloscope front panel and select "Ch1-Ch2". This signal will represent the voltage drop on R1 resistor, V(R1). Here is a picture showing Ch1(yellow), Ch2(blue), and Math(red) traces:

- Use the built-in "Measure" function of the oscilloscope to measure the voltage levels of the channel 1, channel 2, and "Math" traces. Select "Mean" from the measure menu, like it is shown in the picture below:

- Insert a screenshot of the oscilloscope display showing channel 1, channel 2, Math signals, and the measured values.
- Determine Ix from the voltage measured at node B of the circuit (Channel 2). In the waveforms example shown above Ix = 52.2mA, which is determined by translating 52.2mV measured on Ch2 to 52.2mA as described in the theory section of this lab.
- Divide V(R1)/Ix and explain what this quantity represents.

# Step 3

- Setup the power supply voltage to 4V.
- Repeat the procedure at step 2 and record the V(R1)/Ix calculated value
- Insert a screenshot of the oscilloscope display showing channel 1, channel 2, Math signals, and the measured values.

# Step 4

- Setup the power supply voltage to 3V.
- Repeat the procedure at step 2 and record the V(R1)/Ix calculated value
- Insert a screenshot of the oscilloscope display showing channel 1, channel 2, Math signals, and the measured values.

# Step 5

- Setup the power supply voltage to 2V.
- Repeat the procedure at step 2 and record the V(R1)/Ix calculated value
- Insert a screenshot of the oscilloscope display showing channel 1, channel 2, Math signals, and the measured values.

# Step 6

- Setup the power supply voltage to 1V.
- Repeat the procedure at step 2 and record the V(R1)/Ix calculated value
- Insert a screenshot of the oscilloscope display showing channel 1, channel 2, Math signals, and the measured values.

# Step 7

- Setup the power supply voltage to 0V.
- Repeat the procedure at step 2 and record the V(R1)/Ix calculated value
- Insert a screenshot of the oscilloscope display showing channel 1, channel 2, Math signals, and the measured values.
- Comment on any issues you have encountered or any difference between this step and previous steps.

# Step 8

- Insert the V(R1)/Ix calculated values at Steps 2-7 in the table below:

| Vx=5V | Vx=4V | Vx=3V | Vx=2V | Vx=1V | Vx=0V
--- | --- | --- | --- | --- | --- | ---
Ix |  |  |  |  |  |
V(R1)/Ix |  |  |  |  |  |

- Comment on the variation of the V(R1)/Ix values as function of the power supply voltage.
- Did we prove Ohm's law? Explain your answer.