What is the formula for calculating current (I) when voltage (E) and resistance (R) are known?

I = E ÷ R. Current equals voltage divided by resistance.

Using Ohm's Law, what is the voltage across a 20-ohm resistor carrying 3 amperes?

E = I × R = 3 × 20 = 60 volts.

What is the formula for electrical power (P) when voltage (E) and current (I) are known?

P = E × I. Power equals voltage multiplied by current.

How many watts does a 120-volt circuit consume when drawing 15 amperes?

P = E × I = 120 × 15 = 1,800 watts.

What is the formula for power (P) when only current (I) and resistance (R) are known?

P = I² × R. Power equals current squared multiplied by resistance.

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Circuit Calculations – Electrician Journeyman Exam

Master the essential circuit calculations tested on the Electrician Journeyman Exam. This 32-card deck covers Ohm's Law, power formulas, series and parallel circuits, voltage drop, and load calculations to help you pass with confidence.

32 cards Intermediate Ohm's Law & Power Formulas Series Circuits Parallel Circuits Voltage Drop Calculations Load & Demand Calculations

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