Electronics: IntroQuantities:VoltageCurrentPowerDevices:ResistorCapacitorInductorLEDTransistorOp-AmpLaws:Ohms LawKirchhoffs Laws

Voltage

VoltageVoltage = pressure that pushes electrons through circuitWater analogy: voltage = altitude of water

Current

CurrentCurrent = flow of electrons through circuitWater analogy: current = flow of water

Powerhttp://en.wikipedia.org/wiki/Hydroelectrichttp://www.usbr.gov/power/data/sites/glencany/glencany.htmlhttp://www.wapa.gov/newsroom/cct/2005/july15/27no141a.htm

Powerhttp://en.wikipedia.org/wiki/Hydroelectrichttp://www.usbr.gov/power/data/sites/glencany/glencany.htmlhttp://www.wapa.gov/newsroom/cct/2005/july15/27no141a.htmPower = voltage x currentWater analogy: power = altitude drop x flow

Resistor

ResistorResistor reduces current flowWater analogy: flow less for winding river

Capacitor

CapacitorCapacitor stores chargeWater analogy: tank stores water

Inductorhttp://www.magnariders.com/html/Rides/rally/2005_Rally.html

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H

InductorInductor creates magnetic field opposing current changeWater analogy: mill wheel with inertia opposes flow changehttp://www.magnariders.com/html/Rides/rally/2005_Rally.html

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LEDhttp://www.furuier.com/english/product/index0.htmhttp://www.xmission.com/~m3lody/junk/xmas2002/lit_waterfall1.jpg

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D

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LEDLED lights up and acts like voltage dropWater analogy: lit waterfallhttp://www.furuier.com/english/product/index0.htmhttp://www.xmission.com/~m3lody/junk/xmas2002/lit_waterfall1.jpg

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D

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Transistor

TransistorTransistor current flow controlled by second small current flowWater analogy: spillway for dam controlled by hydraulic line

Op-Amp

Op-AmpOp-amp magnifies voltage across inputsWater analogy: Lever translates small pressure into high pressure

Ohms Law

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Ohms LawCurrent in resistor = voltage / resistanceWater analogy: flow = altitude drop / length of river

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Kirchhoffs Voltage Law

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Kirchhoffs Voltage LawSum of voltage drops around loop = 0Water analogy: total altitude change for loop = 0

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Kirchhoffs Current Law

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Kirchhoffs Current LawSum of current flowing out of node = 0Water analogy: what flows in must flow out

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