calculate effective resistance between
Answers
Calculating the equivalent resistance (REQ) of resistors in parallel by hand can be tiresome. This tool was designed to help you quickly calculate equivalent resistance, whether you have two or ten resistors in parallel. To use it, just specify how many parallel resistors there are and the resistance value for each one.
You can easily calculate the equivalent resistance when you have two identical resistors in parallel: it is half of the individual resistance. This is handy when you need a specific resistance value and don't have an appropriate part readily available. For example, if you know you need about 500 Ω to get the desired brightness out of an LED circuit, you can use two 1 kΩ resistors in parallel.
Keep in mind that the current through an individual resistor does not change when you add resistors in parallel, because adding resistors in parallel does not affect the voltage across the resistors' terminals. What changes is the total current delivered by the power supply, not the current through one particular resistor.