《电路》（英文版）1-4 Resistance and Source combination

81-4 Resistance and Source combination The series combination of resistors R R R 十 R R.=R,+R,+…+R The series combination of voltage sources: Several voltage sources in series may be replaced by an equivalent voltage source having a voltage equal to the algebraic sum of the individual sources q

The series combination of resistors: §1-4 Resistance and Source combination . Several voltage sources in series may be replaced by an equivalent voltage source having a voltage equal to the algebraic sum of the individual sources. The series combination of voltage sources: eq =1 + 2 ++ N Req = R1 + R2 ++ RN − +  s i R1 R2 RN − +  s Req i

The parallel combination of current sources The parallel current sources may also be combined by algebraically adding the individual currents, and the order of the parallel elements may be rearranged as desired. Example: 64 0915 44 0.9 2+09=U/3+U/6∵i3=b/3 2A =3.33 GU3 ∴b=10 3 10 18)15=4031

The parallel combination of current sources: The parallel current sources may also be combined by algebraically adding the individual currents, and the order of the parallel elements may be rearranged as desired. Example: 2+ 0.9i 3 = / 3+ / 6 i 3 = / 3  = 10 i 3 = 3.33 P ) 15 4.63W 18 10 ( 2 15 = = 6 3 3 i 0 9 3 . i 2A − +  6 6 15 3 9 3 i 3 0.9i 6A 4A

The parallel combination of voltage sources Voltage sources in parallel are permissible only when each has the same terminal voltage at every instant The series combination of current sources: Two current sources may not placed in series unless each has the same current, including sign, for every instant of time. A voltage source in parallel or series with a current Source +D 十 R R

A voltage source in parallel or series with a current source: The parallel combination of voltage sources: Voltage sources in parallel are permissible only when each has the same terminal voltage at every instant. The series combination of current sources: Two current sources may not placed in series unless each has the same current, including sign, for every instant of time. + s − s i  + − s i + − − +  s i − +  s R i   s i + − R i − +  s  s i