Bruce E. Amrein, MES, MBA, CTS Electricity George Westinghouse, Jr. (1846 – 1914) Thomas Alva Edison (1847 – 1931) Electricity & Electronics Bruce E. Amrein, MES, MBA, CTS

ELECTRICITY: AN ANALOGY

VOLTAGE (E) The volt is a measure of electric potential. Electrical potential is a type of potential energy, and refers to the energy that could be released if electric current is allowed to flow. The SI* unit of voltage is the Volt. E= Electro-motive Force; the voltage developed by any source of electrical energy such as a battery * SI= International System of Units Alessandro Volta (1745 – 1827)

CURRENT (I) An electric current is a flow of electric charge. In electric circuits this charge is often carried by moving electrons in a wire. The SI* unit for measuring an electric current is the ampere (A), which is the flow of electric charge across a surface at the rate of one coulomb per second. Electric current is measured using a device called an ammeter. 1000 milliamps = 1 Ampere André-Marie Ampère (1775 – 1836)

RESISTANCE (Ω) The resistance of an electrical conductor is a measure of the difficulty to pass an electric current through that conductor. Electrical resistance shares some conceptual parallels with the notion of mechanical friction. The SI unit of electrical resistance is the Ohm [Symbol: Ω (Omega)] A resistor is an electrical component. Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits Georg Simon Ohm (1789 – 1854)

DIRECT CURRENT or ALTERNATING CURRENT Direct current is the one way flow of electrical charge from a positive to a negative charge. Batteries produce direct current. Direct Current is different than alternating current because the charge only flows in one direction. Thomas Edison is credited for promoting direct current. Alternating Current is when charges flow back and forth from a source. AC flows in the form of a sine wave, back and forth– 60 times per second in the U.S. Nikola Tesla was a pioneer in the advancement of alternating current. It is the way we receive our electricity (for our houses, businesses, etc.) Alternating Current: In the US, 60 cycles per second, or 60 Hertz, named after Heinrich Rudolf Hertz (1857 – 1894)

SYMBOLOGY & NOTATION Voltage, symbolized by the letters “E” or “V”; measured in volts. Current, symbolized by the letter “I”; measured in amps– short for amperes. Small currents, symbolized by the letter “I”; measured in milliamps (1/1000th of an amp). Resistance, symbolized by the letter “R”, measured in ohms (Ω).

OHM’S LAW Defines the relationship between voltage (E), current (I), and resistance (R). These basic electrical units apply to direct current, or alternating current. Ohm’s Law is the foundation of electronics and electricity. Ohm established in the late 1820s that if a voltage was applied to a resistance then “current would flow and then power would be consumed.”

ELECTRICAL SYMBOLS Load Wire (Resistor) Switch Batteries Lamp AC power AN ELECTRICAL CIRCUIT PICTORIAL SCHEMATIC

WHAT YOU NEED TO KNOW ABOUT RESISTORS Resistors are often in series and parallel configurations in circuits Series combination R1 + R2 + R3 = RT Parallel combination 27-1 Resistors in a circuit 1 1 1 1 R1 R2 R3 Req + + =

LAMPS IN SERIES OR PARALLEL CIRCUITS 27-1 Resistors in a circuit

MEASUREMENTS: DIGITAL MULTIMETER DC VOLTAGE DC AMPS (ma) RESISTANCE

LAB: RESISTOR COLOR CODES Goals: Learn Color Codes Measure Resistance Measure DC Voltage Measure Current

RESISTOR COLOR CODES & MEASUREMENT LAB: RESISTOR COLOR CODES & MEASUREMENT Goal Measure Resistance SET METER ON 2000 Ω SCALE Ω GREEN BROWN RED ORANGE BROWN BLACK BLACK WHITE BROWN RED RED RED

RESISTOR COLOR CODES & MEASUREMENT LAB: RESISTOR COLOR CODES & MEASUREMENT SET METER ON 2000 Ω SCALE 510 Ω 1000 Ω 2000 Ω 3900 Ω

RESISTOR COLOR CODES & MEASUREMENT LAB: RESISTOR COLOR CODES & MEASUREMENT Goal: Measure Resistance Series Combinations Parallel Combinations

RESISTOR COLOR CODES & MEASUREMENT LAB: RESISTOR COLOR CODES & MEASUREMENT Goal: Measure Resistance Series Combinations Parallel Combinations R1 + R2 = RT 510 Ω + 1000 Ω = 1510 Ω 1 1 1 R1 R2 Req + = 1 1 1 3900 Ω 2000 Ω 1322 Ω + =

LAB: VOLTAGE AND CURRENT Goal: Measure Voltage Measure Current V 9.40 v SET METER ON DC VOLTAGE SCALE: 20 VOLTS

VOLTAGE & CURRENT– BUILD A CIRCUIT LAB: VOLTAGE & CURRENT– BUILD A CIRCUIT Goal: Measure Voltage Measure Current R1 + R2 = RT 510 Ω + 1000 Ω = 1510 Ω RED = PLUS (+) R1 R1= 510 Ω R2 = 1000 Ω R2

MEASURE VOLTAGE & CURRENT LAB: MEASURE VOLTAGE & CURRENT Goal: Measure Voltage Measure Current SET METER ON DC AMPERE SCALE: 20 mA V 6 mA mA V2 VT V3 I R1= 510 Ω R2 = 1000 Ω R1 R2 ?? v V SET METER ON DC VOLTAGE SCALE: 20 VOLTS

MEASURE VOLTAGE & CURRENT LAB: MEASURE VOLTAGE & CURRENT Goal: Measure Voltage Measure Current VT 9.4 Volts V1 3.18 V2 6.22 I 6.2 mA mA V1 VT V2 I R1= 510 Ω R2 = 1000 Ω R1 R2

RESISTANCE: A PRACTICAL EXAMPLE ELECTRICAL POWER DISTRIBUTION 10,000 V 100,000 V at 10 Amperes Voltage Loss= 1% TOP EXAMPLE ΔE= IR ΔE= 10A x 100 Ω ΔE = 1000 volts BOTTOM EXAMPLE ΔE= IR ΔE= 100A x 100 Ω ΔE = 10,000 volts 100 miles @ 1 Ω per mile = 100 Ω Power = 1 Million Watts (1 MW) Wire= #3AWG Copper 10,000 V 10,000 V at 100 Amperes Voltage Loss= 100% X X

WHAT CAN YOU DO WITH A MULTIMETER? Check battery voltage (DC VOLTS) Check Power Supplies (AC or DC VOLTS) Check fuses (RESISTANCE) Check household receptacles (AC VOLTS) 120 Volts (AC) 0 Volts 120 Volts (AC)

Are there any questions? Thank you! Are there any questions?