Security Industry Math Formula Reference us at

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1 Security Industry Math Formula eference us at 716-A Lakeside Drive W., Mobile, Alabama 36693

2 General Formulas Ohm s Law E = I x I = E = E I E = Voltage in Volts I = Current in Amps = esistance in Ohms Power Formulas P = I x E P = I 2 x P = E 2 Series Formulas Series Circuit Laws Voltage Division E T = E 1 + E 2 + E n I T = I 1 = I 2 = I n T = n E U = E T U T U = Unknown Value Parallel Formulas General Parallel Circuit Laws Parallel Circuit Laws (for two devices only) E T = E 1 = E 2 = E n I T = I 1 + I 2 + I n T = or Product Sum = 1 1/ 1 + 1/ 2 + 1/ n Current Division I 1 = I T 2 I 2 = I T Parallel Circuit Laws (if all resistors have the same value) = # of All esistors

3 E = I x P I P x I = E P E P = E I P E 2 I 2 P P = I x E E 2 I 2 x Common Symbols & Units of Measurement Symbol Unit Measurement of V Volt Voltage Ω Ohm esistance A Amp Current none Coulomb Charge W Watt Power Hz Hertz Frequency F Farad Capacitance H Henry Inductance Series vs. Parallel Circuits Series Parallel Voltage Additive Equal at all points Current Equal at all points Additive esistance Additive Total will be less than smallest resistor Power Additive Additive

4 Electronic Formulas Work Sheet Device Ohm s Law is given in chart Power (watts) E (voltage) (volts) E = I x I (current) (amps) esistance (ohms) Device 1 P1 E1 I1 1 Device 2 P2 E2 I2 2 Totals Pt Et It t E = I x I = E/ = E/I Tables Device Power E (voltage) I (current) esistance Device Watt s Law is given in chart Power (watts) E (voltage) (volts) Scratch Pad P = E x I I (current) (amps) esistance (ohms) Device 1 P1 E1 I1 1 Device 2 P2 E2 I2 2 Totals Pt Et It t P = I x E I = P/E E = P/I Totals Device Power E (voltage) I (current) esistance Totals Device Power E (voltage) I (current) esistance Totals Device Power E (voltage) I (current) esistance Totals

5 Conversions Volts (V) To Convert: To: Do This: mv V Divide millivolts by 1,000 V mv Multiply volts by 1,000 Voltage is shown as E in formulas such as Ohm s Law..001 volts = 1/1000 volts = 1 millivolt (mv) Amps (A) To Convert: To: Do This: ma A Divide milliamperes by 1,000 μa A Divide microamperes by 1,000,000 A ma Multiply amps by 1,000 A μa Multiply amps by 1,000,000 Amperage is shown as I in formulas such as Ohm s Law..001 amps = 1/1000 amps = 1 milliampere (ma) amps = 1/1,000,000 amps = 1 microampere (μa) Ohms (Ω) - esistance To Convert: To: Do This: KΩ Ω Multiply kilohms by 1,000 MΩ Ω Multiply megaohms by 1,000,000 Ω KΩ Divide ohms by 1,000 Ω MΩ Divide ohms by 1,000,000 esistance is shown as in formulas such as Ohm s Law. 1,000 ohms = 1 kilohm (KΩ) 1,000,000 ohms = 1 megaohm(mω) Watts (W) Power To Convert: To: Do This: mw W Divide milliwatts by 1,000 W mw Multiply watts by 1,000 Power is shown as P in formulas such as Watt s Law..001 watts = 1/1000 watt = 1 milliwatt (mw) watts = 1/1,000,000 watt = 1 microwatt (μw) Make sure all values are converted to Volts, Amps, Ohms or Watts before using any formulas.

6 esistor Color Code A color code is used to identify these ratings: Second Digit Number of Zeros Tolerance 0 Black 1 Brown 2 ed 3 Orange 4 Yellow 5 Green 6 Blue 7 Violet 8 Gray 9 White First Digit of Value Comparative Sizes of esistors Length Diameter Power Dissipation /8 Watt /4 Watt /2 Watt Watt Watts 20% No Band 10% Silver 5% Gold Typical Wire esistances Wire Gauge 1000 at 68 F 1 at 68 F 1000 at 149 F 1 at 149 F Fire Alarm Minimum Cable Size Size (AWG) Minimum Number of Conductors or larger 1

7 Conversions & Equivalents Cubic Measure 1,728 cubic inches 1 cubic foot 27 cubic feet 1 cubic yard 128 cubic feet 1 cord (wood) 231 cubic inches 1 US Standard Gallon Dry Measure 2 pints 1 quart 8 quarts 1 peck 4 pecks 1 bushel Metric Equivalents - Linear Measure 1 centimeter inches 1 inch 2.54 centimeters 1 foot meter 1 meter inches 1 meter yards 1 yard meter 1 rod meters 1 kilometer miles 1 mile kilometers Liquid Measure 2 pints 1 quart 4 quarts 1 gallon 31.5 gallons 1 barrel Imperial Liquid Measure 1 US gallon Imperial gallon 1 US gallon liters 1 Imperial gallon US gallons 1 Imperial gallon liters 1 liter US gallons Linear Measure 12 inches 1 foot 3 feet 1 yard 5.5 yards 1 rod Square Measure 144 sq. inches 1 sq. foot 9 sq. feet 1 sq. yard 640 acres 1 sq. mile Metric Equivalents - Square Measure 1 sq. centimeter sq. inch 1 sq. inch sq. centimeter 1 sq. foot sq. meter 1 sq. meter sq. yard 1 sq. yard sq. meter 1 sq. mile sq. kilometers Metric Equivalents - Weights 1 gram ounces 1 ounce grams 1 kilogram pounds 1 pound kilograms 1 metric ton English ton 1 English ton metric tons Temperature Conversions 1 degree Fahrenheit degree Celsius To convert Fahrenheit degrees into Celsius degrees, subtract 32, multiply by 5 and then divide by 9. To convert Celsius degrees into Fahrenheit degrees, multiply by 9, divide by 5 and then add 32. Water freezes at 32 F and 0 C at sea level. Water boils at 212 F and 100 C at sea level.

8 Math eference Math Signs Addition: + Subtraction: Multiplication: or or nothing between characters [example: 2x or 2(x)=2] Division: or / or ) Equal: = Therefore:. Order of Operations 1. If Parentheses ( ) are present, simplify all expressions inside all parentheses first. 2. Apply all exponents (x 2 ). 3. Do all the multiplications, in order, from left to right. 4. Do all divisions, in order, from left to right. 5. Do all additions and subtractions in order from left to right. Definitions Whole Numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 Fractions: a part of something. ½ = 1 2 = 0.5 Numerator: the number above the line in a fraction. Denominator: the number below the line in a fraction. Decimal: a numeral that uses a decimal point (.) to represent a fraction. Squares: Numbers multiplied by themselves shown by exponents (x 2 = x times x). Dividend: the number to be divided. Divisor: the number by which the dividend is to be divided. Quotient: the number resulting from the division of one number by another. emainder: a number left over after dividing. Improper fraction: a fraction where the numerator is equal to or larger than the denominator. Mixed number: a number consisting of a whole number and a fraction. Common Denominator: a quantity into which all the denominators of a set of fractions can be divided. Multiplication Table: x Place Values: Billions ( 9 x 1,000,000,000 ) Hundred Millions ( 8 x 100,000,000 ) Ten Millions ( 7 x 10,000,000 ) Millions ( 6 x 1,000,000 ) Hundred Thousands ( 5 x 100,000 ) Ten Thousands ( 4 x 10,000 ) Thousands ( 3 x 1,000 ) Hundreds ( 2 x 100 ) Tens (1 x 10 ) Ones ( 0 x 1 ) Tenths ( 1 / 10 ) Hundredths ( 2 / 100 ) Thousandths ( 3 / 1,000 ) Ten Thousandths ( 4 / 10,000 ) ,876,543,