3.4.4: Procedure

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1. Using the circuit of Figure 5.3.1 with R1 = 1 k, R2 = 2.2 k, R3 = 3.3 k, and E = 10 volts, determine the theoretical current and record it in Table 5.5.1. Construct the circuit. Set the DMM to read DC current and insert it in the circuit at point A. Remember, ammeters go in-line and require the circuit to be opened for proper measurement. The red lead should be placed closer to the positive source terminal. Record this current in Table 5.5.1. Repeat the current measurements at points B and C.

2. Using the theoretical current found in Step 1, apply Ohm’s law to determine the expected voltage drops across R1, R2, and R3. Record these values in the Theory column of Table 5.5.2.

3. Set the DMM to measure DC voltage. Remember, unlike current, voltage is measured across components. Place the DMM probes across R1 and measure its voltage. Again, red lead should be placed closer to the positive source terminal. Record this value in Table 5.5.2. Repeat this process for the voltages across R2 and R3. Determine the percent deviation between theoretical and measured for each of the three resistor voltages and record these in the final column of Table 5.5.2.

4. Consider the circuit of Figure 5.3.2 with R1 = 1 k, R2 = 2.2 k, R3 = 3.3 k, R4 = 6.8 k and E = 20 volts. Using the voltage divider rule, determine the voltage drops across each of the four resistors and record the values in Table 5.5.3 under the Theory column. Note that the larger the resistor, the greater the voltage should be. Also determine the potentials \(V_{AC}\) and \(V_B\), again using the voltage divider rule.

5. Construct the circuit of Figure 5.3.2 with R1 = 1 k, R2 = 2.2 k, R3 = 3.3 k, R4 = 6.8 k and E = 20 volts. Set the DMM to measure DC voltage. Place the DMM probes across R1 and measure its voltage. Record this value in Table 5.5.3. Also determine the deviation. Repeat this process for the remaining three resistors.

6. To find \(V_{AC}\), place the red probe on point A and the black probe on point C. Similarly, to find \(V_B\), place the red probe on point B and the black probe on ground. Record these values in Table 5.5.3 with deviations.

5.4.1: Simulation

7. Build the circuit of Figure 5.3.1 in a simulator. Using the virtual DMM as a voltmeter determine the voltages at nodes A, B and C, and compare these to the theoretical and measured values recorded in Table 5.5.2.