Resistors in series

What is the resistance of this circuit, consisting of three resistors in series?Consider the circuit in the diagram that has three resistances and a battery connected in series.
  1. How much current flows in this circuit?
  2. How is Ohm’s law applied?
The answer is that the current in the circuit adjusts itself so that the sum of all the voltage drops equals the voltage provided by the battery. Since it is a series circuit, the current I is the same everywhere. In mathematics, the battery voltage V equals the sum of the voltage drops across each of the three resistances, R1, R2, and R3: V=I R 1 +I R 2 +I R 3 Read the text aloud
The current I in the circuit is the same through each resistor; therefore, we can rewrite this equation by grouping the resistances together as V=I( R 1 + R 2 + R 3 ) This equation looks like Ohm’s law if we make the substitution that the total resistance R of the circuit is equal to the sum of all the individual resistances: R= R 1 + R 2 + R 3 This allows us to write the following for the total voltage and the total current: V=IR, I= V R When resistors are connected in series, their total combined resistance is given by equation (17.3). The total resistance is the easiest way to calculate current in a series circuit. The current is the total voltage divided by the total resistance. Read the text aloud Show Voltage divider circuit
(17.3) R= R 1 + R 2 + R 3 +
R  = equivalent resistance (Ω)
R1  = resistance 1 (Ω)
R2  = resistance 2 (Ω)
R3  = resistance 3 (Ω)
Equivalent resistance
series resistors
Two resistors with resistances of 10 Ω and 20 Ω are connected in series with a battery of voltage 10 V. What is the current through the circuit?
Asked: total current I through the circuit
Given: voltage V = 10 V; resistances R1 = 10 Ω and R2 = 20 Ω
Relationships: Ohm’s law I = V/R;
equivalent resistance for series resistors: Req = R1 + R2
Solution: The equivalent resistance for the series circuit is
Req = R1 + R 2 = 10 Ω + 20 Ω = 30 Ω
The current is then I= V R eq = 10 V 30 Ω =0.33 A
Answer: I = 0.33 A.
Read the text aloud
Seven resistors with resistances of 1, 2, 3, 4, 5, 6, and 7 Ω, respectively, are connected in series. What is their effective resistance? Show

Previous Page Next Page491