26. Circuit Diagrams

Question 1

What is the difference between a series and parallel circuit?

Answer 1

There is a single path for the current to follow. While the parallel, there are multiple paths for the current to flow.

Question 2

What are the rules for resistors in series?

Answer 2

1. First find the equivalent resistance (R_Equivalent = R₁ + R_2….)
2. Then find the equivalent current (I_Equivalent = Vtotal/R_Equivalent)
3. Put the expression I_Equivalent = I₁ = I₂ = I₃, because the current thru all the resistors is the same in series.
4. Then find the voltage drop across each resistor.

• V_Total = V₁ + V₂ + V₃
• V₁ = I_Equivalent * R₁
• V₂ = I_Equivalent * R₂
• V₃ = I_Equivalent * R₃

Question 3

What are the rules for solving circuits with resistors in parallel?

Answer 3

1. First find the equivalent resistance. (1/R_Equivalent = 1/R₁ + 1/R₂ + 1/R₃).
2. Then find the equivalent current (I_Equivalent is the current across the battery).
3. Insert V_Total = V₁ = V₂ = V₃, because the voltage drop across the resistors is all the same.
4. The current in each path is solved with V=IR. (I₁ = V_Total/R₁, I₂ = V_Total/R₃, I₃ = V_Total/R₃
5. All the smaller currents in different paths should add up to I_Equivalent

• I_Equivalent = I₁ + I₂ + I₃