MW Light bulbs in series connection Note: The symbol represents a light bulb which can be treated as a resistor. ' 4' 0'4 V DMM Vs DMM 5 Figure 4(a) One bulb "1 the c1rcu1t Figure 4(b) Two bulbs in series connection '2' '1' '1' DMM VS DMM Figure 4(a) Three bulbs in series connection Figure 4((1) F011? blllbs in series connection Check that the DC power supply #1 is off. Connect the circuit shown in Fig. 4(a). Turn on the DC power supply #1. Record the DMM reading and the observed bulbs' brightness in Table 1. Turn off the DC power supply #1. Repeat steps 1 to 4 for circuit shown in Fig. 4(b). Repeat steps 1 to 4 for circuit shown in Fig. 4(c). Repeat steps I to 4 for circuit shown in Fig. 4(d). Repeat steps 1 to 4 for circuit shown in Fig. 4(d) but with one bulb is removed from its socket. waewewww Table 1 DMM reading and observed bulbs' brightness for the circuits in Fig. 4. Source Cases DMM Current Current Observed Voltage Vs through power through each brightness reading (mA) supply (mA) bulb (mA ) Fig. 4(a) 21017 Fig. 4(b) SV 1413 Fig. 4(c) 116. 2 Fig. 4(d) Fig. 4(d) but with one light bulb removed O Questions on Measurement #1: 1. Is the current through the power supply and each bulb (in Table 1) increasing or decreasing with increasing the number of bulbs from Fig. 4 (a) to Fig. 4 (d)? Why? 2. Is there any correlation between the current through each bulb and the observed bulbs' brightness listed in Table 1? If yes, is the correlation consistent with P = IV = 12R? Are the lights at your home connected in series? Why? Measurement #2: Light bulbs in parallel connection (Fig. 5) 5V VS 5V R1 R DMM DMM Figure 5(a) One bulb in the circuit Figure 5(b) Two bulbs in paranel connection 5V 5V DMM DMM Figure 5(c) Three bulbs in parallel connection Figure 5(d) Four bulbs in parallel connection 1. Check that the DC power supply #1 is off. Connect the circuit shown in Fig. 5(a). 2 . Turn on the DC power supply #1. Record the DMM reading and the observed bulbs' brightness in Table 2. 4. Turn off the DC power supply #1. 5. Repeat steps 1 to 4 for circuit shown in Fig. 5(b). 206. Re 7. R pent steps 1 lo 4 for circuit shots-u in l-'ig. 5(a). Repeat steps 1 to d for circuit shoun in g. 51d)- epent steps 1 to 4 forcincuit shown in Fig. Std) hut With one bulb is removed From in \"Ck\"- anti \"l-'IYC'J hulhs' brightness For the circuits in Fig. 5. _ ('nscs \"MM ('urrent ('urrent reading through power through each supply (mm Observed'1 brightness ' Fig. 5(d} but with one li - ht bulb removed Questions on Measurement #2: l. is the current through the power supply and each bulb [in Table 2) increasing 0" decreasing With increasing the number of bulbs from Fig. 5 (a) to Fig. 5 (d)? Why? 2. Is there any correlation between the current through each bulb and observed bulbs' brightness? Why? 3. Are the lights at your home connected in parallel? Why? 4. The maximum output current from the DC power supply #1 is 2 A. What is the maximum number of light bulbs (used in this experiment) can be connected in parallel with the DC power supply #1? What will happen if more than 10 such light bulbs are connected in parallel with the DC power supply #l? Measurement #3: Light bulbs in complex connections (Fig. 6} Figure 6 Bulbs in complex connections Check that the DC power supply #1 is off. Connect the circuit shown in Fig. 6. l. 2. Turn on the DC power supply #1. 3. Record the measured current and observed bulbs' brightness in Table 3. 4 5 Turn oil\" the DC power supply it]. Repeat steps I to 4 with a change: use DC power supply #2 (HYI 52A) and set the output voltage to VS=10V. 6. Repeat step 5 with a change: remove light bulb #I from its socket and keep the other three light bulbs in their original places. 21 7. Repeat step 5 with a change: remove light bulb #2 from its socket and keep the other three light bulbs in their original places. 8. Repeat step 5 with a change: remove light bulb #3 from its socket and keep the other three light bulbs in their original places. 9. Repeat step 5 with a change: remove light bulb #4 from its socket and keep the other three light bulbs in their original places. Table 3 DMM reading and observed bulbs' brightness for the circuits in Fig. 6. Source Cases DMM Observed bulbs' brightness Voltage reading bulb #1 bulb #2 bulb #3 bulb #4 VS (mA) SV All 4 light bulbs are in circuit low Very low All 4 light bulbs are in circuit 193. 8 Light bulb #1 is removed 0. 00 Off Off of 10V Light bulb #2 is removed 1710 Light bulb #3 is removed 16612 high high Light bulb #4 is removed 0. 00 off Off Data analysis for Measurement #3: Assume all the four light bulbs in Fig. 6 have the same resistance. From the measured currents in Table determine the current through each light bulb /1, /2, 13, I, and record the values in Table 4. Table 4 Current through each light bulb in Fig. 6 Source Cases I2 I3 I4 Voltage Vs (mA) (mA) (mA) (mA) 5V All 4 light bulbs are in circuit All 4 light bulbs are in circuit Light bulb #1 is removed 10V Light bulb #2 is removed Light bulb #3 is removed Light bulb #4 is removed Questions on Measurement #3: 1. With all 4 bulbs are in circuit (Fig. 6), use the data in Table 4 explain why bulbs #2 and #3 are dimmer at Vs = 5 V than at Vs = 10 V. 2. Using the measured data of current in Table 3 and the data in Table 4 explain: (a) why bulbs #1 and #4 are brighter than bulbs #2 and #3 at both Vs = 5 V and 10 V when all the 4 bulbs are in circuit;(bl why bulbs #3 becomes as bright as hulh all and #4 after bulb #2 is removed {all \"the" mm" are remained in the circuit). 3. Can the lights at your home be connected using the circuit in Fig. 6'? Why? Work to be done: i. 2. 3. 4. Check that the DC power supply #1 is off. , Check that the DC power supply #2 {HY152A) is off. If not, turn voltage to (N then shut it down. Let your TA check your data Tables. If they are OK, your TA will sign them. Clean up your bench. Lab report on Experiment 2 1. 2. Tables 1 to 4 along with their corresponding circuits should be included in your lab report. It is required that the answers to the questiOns on each measurement (listed below Tables 1, 2 and 4) should be included in your lab report. It is required that the answers to the questions in \"Questions and Exercises\" (on next page) should be included in your lab report. The required other contents and format for your lab report can be found in the syllabus You can tear those pages out of the lab manual as a part of your lab report, which contain measured (raw) data and analyzed data, answers to questions. The data sheets must be checked and signed by your lab TA