1 Igniting the Spark of Science! Electricity & Electronics Bruce E. Amrein, MES, MBA, CTS Thomas Alva Edison (1847 – 1931) Nikola Tesla (1856 – 1943)

2 Igniting the Spark of Science! ELECTRICITY: AN ANALOGY

3 Igniting the Spark of Science! Alessandro Volta (1745 – 1827) 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 VOLTAGE (E)

4 Igniting the Spark of Science! André-Marie Ampère (1775 – 1836) 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 milliamps = 1 Ampere

5 Igniting the Spark of Science! Georg Simon Ohm (1789 – 1854) 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

6 Igniting the Spark of Science! 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)

7 Igniting the Spark of Science! 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 (1/1000 th of an amp). Resistance, symbolized by the letter “R”, measured in ohms (Ω). SYMBOLOGY & NOTATION

8 Igniting the Spark of Science! 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.” OHM’S LAW

9 Igniting the Spark of Science! ELECTRICAL SYMBOLS Wire Switch Lamp Load (Resistor) Batteries AC power AN ELECTRICAL CIRCUIT PICTORIAL SCHEMATIC

10 Igniting the Spark of Science! Series combination Parallel combination WHAT YOU NEED TO KNOW ABOUT RESISTORS R 1 + R 2 + R 3 = R T R 1 R 2 R 3 R eq + + = Resistors are often in series and parallel configurations in circuits

11 Igniting the Spark of Science! LAMPS IN SERIES OR PARALLEL CIRCUITS

12 Igniting the Spark of Science! DC VOLTAGE MEASUREMENTS: DIGITAL MULTIMETER RESISTANCE DC AMPS (ma)

13 Igniting the Spark of Science! LAB: RESISTOR COLOR CODES Goals: Learn Color Codes Measure Resistance Measure DC Voltage Measure Current

14 Igniting the Spark of Science! LAB: RESISTOR COLOR CODES & MEASUREMENT SET METER ON 20,000 Ω SCALE GREEN BROWN RED ORANGE BROWNBLACKBLACKWHITE BROWNREDREDRED Goal Measure Resistance Ω

15 Igniting the Spark of Science! LAB: RESISTOR COLOR CODES & MEASUREMENT SET METER ON 20,000 Ω SCALE 510 Ω1000 Ω2000 Ω 3900 Ω

16 Igniting the Spark of Science! LAB: RESISTOR COLOR CODES & MEASUREMENT Goal: Measure Resistance Series Combinations Parallel Combinations

17 Igniting the Spark of Science! LAB: RESISTOR COLOR CODES & MEASUREMENT Goal: Measure Resistance Series Combinations Parallel Combinations 510 Ω Ω = 1510 Ω Ω 2000 Ω 1322 Ω + = R 1 R 2 R eq + = R 1 + R 2 = R T

18 Igniting the Spark of Science! LAB: VOLTAGE AND CURRENT Goal: Measure Voltage Measure Current V 9.40 v SET METER ON DC VOLTAGE SCALE: 20 VOLTS

19 Igniting the Spark of Science! LAB: VOLTAGE & CURRENT– BUILD A CIRCUIT Goal: Measure Voltage Measure Current 510 Ω Ω = 1510 Ω R 1 + R 2 = R T R 1 = 510 Ω R 2 = 1000 Ω RED = PLUS (+) R1R1 R2R2

20 Igniting the Spark of Science! LAB: MEASURE VOLTAGE & CURRENT Goal: Measure Voltage Measure Current V 6 mA SET METER ON DC AMPERE SCALE: 20 mA V ?? v SET METER ON DC VOLTAGE SCALE: 20 VOLTS mA V2V2 VTVT V3V3 I R 1 = 510 Ω R 2 = 1000 Ω R1R1 R2R2

21 Igniting the Spark of Science! Goal: Measure Voltage Measure Current VTVT 9.4Volts V1V1 3.18Volts V2V2 6.22Volts I6.2mA LAB: MEASURE VOLTAGE & CURRENT mA V1V1 VTVT V2V2 I R 1 = 510 Ω R 2 = 1000 Ω R1R1 R2R2

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

23 Igniting the Spark of Science! 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)

24 Igniting the Spark of Science!