How to Calculate Total Resistance in Circuits
Identify a series circuit., Add all resistances together., Start with current and voltage instead., Insert these values into Ohm's Law.
Step-by-Step Guide
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Step 1: Identify a series circuit.
A series circuit is a single loop, with no branching paths.
All the resistors or other components are arranged in a line. , In a series circuit, the total resistance is equal to the sum of all resistances.The same current passes through each resistor, so each resistor does its job as you would expect.
For example, a series circuit has a 2 Ω (ohm) resistor, a 5 Ω resistor, and a 7 Ω resistor.
The total resistance of the circuit is 2 + 5 + 7 = 14 Ω. , If you don't know the individual resistance values, you can rely on Ohm's Law instead:
V = IR, or voltage = current x resistance.
The first step is to find the circuit's current and total voltage:
The current of a series circuit is the same at all points on the circuit.If you know the current at any point, you can use that value in this equation.
The total voltage is equal to the voltage of the supply (the battery).
It is not equal to the voltage across one component., Rearrange V = IR to solve for resistance:
R = V / I (resistance = voltage / current).
Plug the values you found into this formula to solve for total resistance.
For example, a series circuit is powered by a 12 volt battery, and the current is measured at 8 amps.
The total resistance across the circuit must be RT = 12 volts / 8 amps =
1.5 ohms. -
Step 2: Add all resistances together.
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Step 3: Start with current and voltage instead.
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Step 4: Insert these values into Ohm's Law.
Detailed Guide
A series circuit is a single loop, with no branching paths.
All the resistors or other components are arranged in a line. , In a series circuit, the total resistance is equal to the sum of all resistances.The same current passes through each resistor, so each resistor does its job as you would expect.
For example, a series circuit has a 2 Ω (ohm) resistor, a 5 Ω resistor, and a 7 Ω resistor.
The total resistance of the circuit is 2 + 5 + 7 = 14 Ω. , If you don't know the individual resistance values, you can rely on Ohm's Law instead:
V = IR, or voltage = current x resistance.
The first step is to find the circuit's current and total voltage:
The current of a series circuit is the same at all points on the circuit.If you know the current at any point, you can use that value in this equation.
The total voltage is equal to the voltage of the supply (the battery).
It is not equal to the voltage across one component., Rearrange V = IR to solve for resistance:
R = V / I (resistance = voltage / current).
Plug the values you found into this formula to solve for total resistance.
For example, a series circuit is powered by a 12 volt battery, and the current is measured at 8 amps.
The total resistance across the circuit must be RT = 12 volts / 8 amps =
1.5 ohms.
About the Author
Natalie Kim
Enthusiastic about teaching lifestyle techniques through clear, step-by-step guides.
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