How to Add Parallel Resistors

Resistors
••• widerstand, resistor image by Sascha Zlatkov from Fotolia.com

Resistors are electronic components whose main purpose is to help control the amount of current in a circuit. Their property is that of resistance; a high resistance means a lower current flow, and a low resistance means a higher current flow. Resistance depends on both the geometry and composition of the component. The most common types of resistors are made from carbon, and they are found in nearly every circuit.

Resistors may be placed parallel inside a circuit. This means that they are all connected to the same points. To add parallel resistors, you need to use Ohm’s Law.

Instructions

    Recall the properties of resistors in parallel circuits. Because they are connected to the same two points, they each have the same voltage, but the current is divided between them.

    Study Ohm’s Law. Ohm’s Law is is V = IR, where V is the voltage, I the current and R the resistance.

    Use Ohm’s Law to add parallel resistors. The equation is 1/R(Total) = 1/R1 + 1/R2 + 1/R3 + …+ 1/R(Last).

    Apply Step 3 to calculate the total resistance of two resistors placed parallel to each other. The equation is 1/R(Total) = 1/R1 + 1/R2. Use R1 = R2 = 4 ohms. This gives 1/R(Total) = 1/4 ohms + 1/ 4 ohms. The result is 1/R(Total) = 0.25 ohms + 0.25 ohms = 0.5 ohms, and therefore R(Total) is 2 ohms.

    Things You'll Need

    • Calculator
    • Introductory physics text

Related Articles

How to Calculate Resistors in Parallel
How to Calculate 30 KW to Amps
Test Your Knowledge on Middle School Science
About Voltage Reduction Resistor Formula
Characteristics of Aquatic Plants
302 Vs. 304 Stainless Steel
An Electrical Engineer's Vocabulary Words
Is Methanol & Isopropyl Alcohol the Same Thing?
What is the Identity Property of Multiplication?
How to Calculate Output Voltage
How to Convert Pounds Per Square Foot to PSI
How to Calculate Your YTD GPA
How to Lower Amperage
How to Test a Blower Resistor
How to Convert 12 Volt to 6 Volt
How to Find the Cross Sectional Area of a Pipe
How to Calculate Volume of a Rectangular Prism
How to Use a Protractor to Measure a Triangle
How to Reduce Voltage on 12 Volt System to 4 Volt
How to Make a Simple Circuit