Under what conditions would the current undergo no change?

SERIES CIRCUITS VW REFERENCE READING Principles of Electric Circuits: Sectang 81 through 6-4. RELATED PROBLEMS FROM PRINCIPLES OF ELECTRIC CIRCUITS Chapter 5, Problems 1 through 26. OBJECTIVE To verify that the total resistance in a series-connected circuit is the sum of the individual resistances. EQUIPMENT dc power supply 0-10 V DMM or VOM Resistors (+5%): 110 2k12 322 3.9 kn 6.1 kn BACKGROUND When resistors are connected in series, the current that will flow is calculated from a knowledge of the total resistance. The total resistance in this case is simply the spm of the individual resistors, By knowing the total resistance, the voltage required for a desired current or the current resulting from an applied voltage can easily be calculated. One of the purposes of this experiment is to provide you with still more experience in using your DMM. You will use it on the ohms, volts, and milliampe functions in verifying the Series Resistor Rule.

PROCEDURE 1. Calculate the upper and lower limits of the resistance for each resistor and re- cord these in Table 8-1. 2. Use the ohmmeter to measure the actual values of each resistor and record these in the row labeled Rynene 3. Complete Table 8-1 by calculating the upper and lower limits to R. (= R + R +R+ R + R) and then measuring the actual yalue of Rs by series-con- necting the rosistors. Does the measured value equal the sum of the individual measured values? If not, why not? Using a value for V, of 10 V, calculate the nominal, minimum, and maximum values for I in the circuit of Figure 8-1 and record them in Table 8-2. 5. Connect the circuit in Figure 8-1 and adjust V, to a value of 10 V. Measure the current I and record it under Ibon in Table 8-2. (Does it appear consistent with Rees?) Using a value for 1 of 0.5 mA, calculate the nominal, minimum, and maximum values for V. in order to sustain this current through the series combination, Record these in Table 8-9. 7. Connect the circuit and adjust V, until I = 0.5 mA. Measure the voltage and record it in Table 8-3. (Does it appear consistent with me?) MAX 3R₂ M Ry RA FIGURE 8-1

DATA FOR EXPERIMENT 8 TABLE 8-1 1k02 2k0 3.9 k125.1 km Rx = 15 kn Rule Rau Rr TABLE 8-2 Inom (mA) (mA) ܩܢܕܐ BLE V, – 10 V 7 I(MA) I (MA) TABLE 8-3 I – 0.5 mA VEX (V) V. (V)

Name Date QUESTIONS FOR EXPERIMENT 8 1. If the moagured value of Ry did not equal the sum of the indi- vidually measured resistances, you might conclude that (a) the resistors had changed in value (b) the resistors were out of tolerance (c) the ohmmeter measurements are subject to some error (d) all of the above 2. Three regiators of value 1 k12, 2 k., and 3 k 2. each having a tolerance of 15 percent, are series-connected across a 10 V source. The smallest current you would expect to flow in the circuit is (a) 1.59 mA (b) 1.67 mA (c) 1.75 mA (d) none of these 3. The current through each resistor in a series-connected circuit such as that in Figure B-1 is the same. (a) True (b) False 4. If the resistor tolerances in this experiment had been 10 per- cent, the maximum current through the series combination with a 10 V source would have been (a) 61 mA (b) 606 A (c) 741 A (d) 667 mA 5. If any resistor in a series circuit ia reduced in value, the total current will increase. Explain why this is so. CARLY COSTUANDUSPAUDAZNAISILTA VUOTASIS GLO W 6. If two resistors in a series circuit guffer a change in resistance such that one increases by 10 percent and the other decreases by 10 percent, explain why the current will not necessarily stay constant. Under what conditions would the current undergo no change? CLEESORIO