OHM’S LAW5OHM’S LAW 4 Ohm’s law states the fundamental relationship between voltage, current, and resistance.QUESTIONWhat is the algebraic formula for Ohm’s law? ANSWERV I R5 3 This is the most basic equation in electricity, and you should know it well. Some electronics books state Ohm’s law as E 5 IR. E and V are both symbols for voltage. This book uses V to indicate voltage. When V is used after a number in equations and circuit diagrams, it represents volts, the unit of measurement of voltage. Also, in this formula, resistance is the opposition to current ﬂow. Larger resistance results in smaller current for any given voltage. 5 Use Ohm’s law to ﬁnd the answers in this problem. QUESTIONSWhat is the voltage for each combination of resistance and current values? A. R 5 20 ohms, I 5 0.5 amperes V 5 B. R 5 560 ohms, I 5 0.02 amperes V 5 C. R 5 1,000 ohms, I 5 0.01 amperes V 5 D. R 5 20 ohms I 5 1.5 amperes V 5 Book Author c01 V1 07/04/2012 2:42 PM c01.indd 57/4/2012 2:44:23 PM