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Note: Items in red are measurements that must be made as you do the experiment.

Introduction

You will design and build a resistive network (either by theory or by trial and error) such that that the measured equivalent resistance is numerically equal to the last four digits of your BYU ID number in Ohms. The last four digits of your BYU ID number (include leading zeros):  This is your "target resistance."

Nominal and Actual Resistances:

Many resistors are labeled with bands that indicate the value of the resistance. This value is the "nominal resistance." Most resistors, however, have actual resistances that are only within about 10% of the nominal value. (High precision resistors can be obtained when needed, but they can be quite costly. In order to obtain more accuracy, you need to use an ohmmeter to measure the actual resistance of each resistor you use. These numbers should be entered in the blanks labeled R₁ to R₈ below.

Series:

Connect exactly four resistors in series so that the total resistance is the smallest number you can get that is larger than the target resistance. (For example, if the target resistance is 8432, you would 5 kΩ + 2 kΩ + 1 kΩ +500 Ω =8500 Ω.)  Arrange them so that R1 is the smallest resistance, R2 is next smallest, etc. R1: Ω R2: Ω R3: Ω R4: Ω

Figure 1

Parallel:

Now connect a resistor, R5, in parallel with R4. Choose the value of R5 to be the largest resistor that keeps the total resistance greater than the target resistance. Repeat by connecting other resistors in series with R3, R2, and R1, as shown in Figure 2.  Carefully note which resistors are in parallel pairs, as the grading software won't notice if your order is wrong! R5: Ω R6: Ω R7: Ω R8: Ω   Measure the total resistance of the eight resistors and compare this value to the value that you get by using series-parallel reduction of the circuit. For the calculation, use the measured values of each resistor that you entered in blanks R1 to R8 above. Total resistance, measured: Ω Total resistance, calculated: Ω Note that these should be quite close.

Figure 2