Question

(d) Which resistor draws a current of 5A when connected across terminals A and B shown in figure 4. 122 - A + 120V = 241 3 OB - Figure 4 [6 marks] (e) Find V across the open circuit shown in figure 5. 5k_2 M 4mA 3k_2 10k12 = 80 35512 5V Figure 5 [7 marks]

Answer 1

122 Let the resistor be Rr as shown in Figure. R $2412 120V B 2242 th 120V 12ut12, Ut wij U UUUUU 3 By useing thevenin's theorem. Vitha thevenin's voltage acrors A&B= Open circuit Voltage Uthe voltage across 24-2 reislov o uth = 120(-24) = 80v. Rth: thevenin's resistance is equivalent resista 122 OA ' 242 € Rth on Rthe 12x24 = 82. . Rth = parallel of 122&242 12424 Than the circuit becomes. - Rth=82 A Let 'R' is required resistance value current through resistance R'. is equal to = ( 80 + 1th=80V NB 18+R But gives it is SAS ( R ) R=85

@ given circuit is 3K ihr Vi lok 5K M È sou 35kn UMA Hot 15 V LEKU By useing source transfermation may ban can be changed as uma 3K2 5KA + va uxio x 5x10- 20V Series wilt 5km. than Tok2 wortli H ot F80v $5km 20v Hito- By using Source transtes mation : TOK 15V v - 5KM - mot 20 3628 Skaare in parallel than result is 346 = 1.845 KR. TORN tv mot lokno 5kr + § 1.875 kr 20V 0.80 > Y 3x10 1 15V By useing source transformation than 108152. loka : 5 kn stors are 20v All resistors are neglected because there is no current ig pasting through it be 15V kulto loop gives i o o t o 50 -20 +1 +15 =0 15V V=-45V