Derivation of formula for resistors in parallel
The voltage across each resistor is the same as the battery voltage
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Let's see if we can derive the equation for finding the effective resistance of parallel circuits.
This is the strategy
- write an equation saying: current drawn from the battery = sum of the currents through each resistor
- write V/R instead of I
- use the fact that the voltage across each resistor is the same as the battery voltage
- divide by V all the way through since it's the same both sides, which leaves us our expression in R