Soal dan Pembahasan Rangkaian Listrik Seri dan Paralel

Di tulisan ini, kita akan belajar bagian dari teknik elektro, mengenai soal dan pembahasan rangkaian listrik seri dan paralel, yang sebelumnya telah dijelaskan mengenai teori rangkaian listrik seri dan paralel. 

1. What is the total resistance of three 20-Ohm resistors connected in series?
    Jawab :
    Rseri = R1 + R2 + R3 = 20 +20 +20 = 60 Ohm

2. A car has a 3-V, 1.5 Ohm dash light and a 3-V, 1.5 Ohm taillight connected in series to a battery delivering 2 A. Find the battery voltage and total resistance of the circuit.

     Jawab :
     Rtotal = R1 + R2 = 1,5 + 1,5 = 3 Ohm
     Vt = I * Rtotal = 2 * 3 = 6 V

3.  A lamp using 10 V, a 10 Ohm resistor drawing 4 A, and a 24 V motor are connected in series. Find the
total voltage and the total resistance.
     Jawab :
     Vresistor = R * I = 10 * 4 = 40 V
     Vtotal = Vlamp + Vres + Vmotor = 10 + 40 + 24 = 74 V

     Karena rangkaian seri, maka arus yang mengalir pada setiap komponen adalah sama, maka Itotal = 4 A

     Rtotal  = Vtotal / Itotal = 74 / 4 = 18,5 Ohm

4.  Given I = 2 A, R1 = 10 , V2 = 50 V, and V3 = 40 V, find V1, VT , R2, R3, and RT

    Jawab :
    Karena rangkaian seri, maka arus yang mengalir pada setiap komponen adalah sama.
    V1 = I * R1 = 2 * 10 = 20 V
    Vtotal = V1 + V2 + V3 = 20 + 50 + 40 = 110 V
    R2 = V2 / I = 50 / 2 = 25 Ohm
    R3 = V3 / I = 40 / 2 = 20 Ohm
    Rtotal = Vtotal / I = R1 + R2 + R3 = 110 / 2 = 55 Ohm 

5. A voltage divider consists of a 3000 Ohm , a 5000 Ohm , and 10 000 Ohm resistor in series. The series current is 15 mA. Find (a) the voltage drop across each resistance, (b) the total voltage, and (c) the total
resistance.
   Jawab : 
    I = 15 mA

   (a) V1 = I * R1 = 15 * 3 = 45 V
        V2 = I * R2 = 15 * 5 = 75 V
        V3 = I * R3 = 15 * 10 = 150 V

   (b) Vtotal = I * Rtotal = 15 * 18 =  270 V
 
   (c) Rtotal = 3 + 5 + 10 kOhm = 18 kOhm

 6. A 12-Ohm spotlight in a theater is connected in series with a dimming resistor of 32 Ohm . If the voltage drop across the light is 31.2 V, find the missing values indicated in picture.

 
     Jawab :
     Rt = R1 + R2 = 12 + 32 = 44 Ohm
     I = I1 = I2 = V1 / R1 = 31,2 / 12 = 2,6 A
     V2 = I * R2 = 2,6 * 32 = 83,2
     Vt = V1 + V2 = 31,2 + 83,2 = 114,4 V

 7. Find voltage values at points A, B, C, and D shown in the circuit (Fig below) with respect to ground.

     Jawab :
     Rtotal = R1 + R2 + R3 = 5 + 10 + 15 = 30 Ohm
     I = Vtotal / Rtotal = 60 / 30 = 2 A
     Va = Vtotal = 60 V (tidak ada hambatan)

    V1 = I * R1 = 2 * 5 = 10 V
    V1 = Va - Vb
    Vb = Va - V1 = 60 - 10 = 50 V

    V2 = I * R2 = 2 * 10 = 20 V
    V2 = Vb - Vc
    Vc = Vb - V2 = 50 - 20 = 30 V

    V3 = I * R3 = 2 * 15 = 30 V
    V3 = Vc - Vd 
    Vd = Vc - V3 = 30 - 30 = 0 V