# 3.5.4: Procedure

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1. Using the circuit of Figure 6.3.1 with R1 = 1 k, R2 = 2.2 k and E = 8 volts, determine the theoretical voltages at points A, B, and C with respect to ground. Record these values in Table 6.5.1. Construct the circuit. Set the DMM to read DC voltage and apply it to the circuit from point A to ground. The red lead should be placed at point A and the black lead should be connected to ground. Record this voltage in Table 6.5.1. Repeat the measurements at points B and C.

2. Apply Ohm’s law to determine the expected currents through R1 and R2. Record these values in the Theory column of Table 6.5.2. Also determine and record the total current.

3. Set the DMM to measure DC current. Remember, current is measured at a single point and requires the meter to be inserted in-line. To measure the total supplied current place the DMM between points A and B. The red lead should be placed closer to the positive source terminal. Record this value in Table 6.5.2. Repeat this process for the currents through R1 and R2. Determine the percent deviation between theoretical and measured for each of the currents and record these in the final column of Table 6.5.2.

4. Crosscheck the theoretical results by computing the two resistor currents through the current divider rule. Record these in Table 6.5.3.

5. Consider the circuit of Figure 6.3.2 with R1 = 1 k, R2 = 2.2 k, R3 = 3.3 k, R4 = 6.8 k and E = 10 volts. Using the Ohm’s law, determine the currents through each of the four resistors and record the values in Table 6.5.4 under the Theory column. Note that the larger the resistor, the smaller the current should be. Also determine and record the total supplied current and the current $$I_X$$. Note that this current should equal the sum of the currents through R3 and R4.

6. Construct the circuit of Figure 6.3.2 with R1 = 1 k, R2 = 2.2 k, R3 = 3.3 k, R4 = 6.8 k and E = 10 volts. Set the DMM to measure DC current. Place the DMM probes in-line with R1 and measure its current. Record this value in Table 6.5.4. Also determine the deviation. Repeat this process for the remaining three resistors. Also measure the total current supplied by the source by inserting the ammeter between points A and B.

7. To find $$I_X$$, insert the ammeter at point X with the black probe closer to R3. Record this value in Table 6.5.4 with deviation.

## 6.4.1: Simulation

8. Build the circuit of Figure 6.3.2 in a simulator. Using the virtual DMM as an ammeter determine the currents through the four resistors along with $$I_X$$, and compare these to the theoretical and measured values recorded in Table 6.5.4.

This page titled 3.5.4: Procedure is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by James M. Fiore.