ࡱ> )+( bjbj "jjl2222FOffffffff$K k |9fffffff fffffZ @\2<^0O  Chapters19 & 20- Currents and Circuits Electric Potential (Voltage): To find the electric potential of a power supply, you take the work supplied and divide it by the magnitude of the charge. Voltage (V) = Work V = work 1 volt = 1 joule/coulomb Charge Q Electric Current: Electric current is the measure of the flow of charged particles. It measures how fast the current will flow over a period of time. Current (I) = Electric Charge I = Q 1 ampere (amp) = 1 coulomb/second Time t Electric Resistance: Electric resistance is exactly what is sounds like, it  resists electric current. Resistance, measured in ohms (W) and is found by dividing the voltage by the current. Resistance (W) = Voltage R = V 1 Ohm (W) = 1 volt/amp = 1 J sec/C2 Current I Electric Power: Electric power is similar to our definition of power from earlier this year- how much work is done over time. In electrical circuits, power is found by finding the product of the voltage and the current. Power is measured in Watts (W). Power = current x voltage P = IV 1 Watt = 1 A V = 1 J/s Power = voltage2 P = V2 Power = Energy/time Resistance R Electric companies use a measure of electrical energy used and give a charge for a certain day. They use a measure called kilowatt-hours. It is a combination of how many kilowatts of power are used in a certain length of time. Kilowatt-hours are then multiplied by a cost and that is how you are billed. (1 kilowatt hour = 3.6 x 106 J of energy) Series & Parallel Circuits In electrical circuits, the appliances (resistors) can be arranged so that in order for one to work, every appliance has to be on (series circuit) or you can have on appliance on at a time (parallel circuit.) Your home is a bunch of very complex circuits, mostly parallel. In a series circuit, the total resistance of the circuit is equal to the sum of all of the resistors in the circuit. R = Ra + Rb + Rc + (Vt = Va + Vb + Vc + .) (It = Ia = Ib = Ic=) In a parallel circuit, the total resistance of the circuit is equal to the reciprocal sum of all of the resistors in the circuit. 1/R = 1/Ra + 1/Rb + 1/Rc + (It = Ia + Ib + Ic + .) (Vt = Va = Vb = Vc=) ()H3bFH >B<  9 G  8 9   5H*OJQJ5H*CJaJ H*OJQJ 5>*H*5H* 5OJQJOJQJ5>*5CJ aJ 5CJ aJ M'() 46Bvx; < v w   8 $a$8 9 K L 5H*5H*OJQJ5 1h/ =!"#$% i8@8 NormalCJ_HaJmH sH tH :@: Heading 1$@&5>*CJaJ<A@< Default Paragraph Font z'() !;<;<vw89KL000000000000000000000000000000000000 8     UW:::::: '  w7Eddiestclairt%E:\Physics\circuits formula sheet.docMISPE:\physics\Electricity\Circuits & Current Electricity\circuits formula sheet.doc@CHH4@@@@@@UnknownGz Times New Roman5Symbol3& z ArialEz Times New (W1)"qhy&&;Ն =GJ!20G3H!Chapter 20- Currents and CircuitsEddieMISOh+'0 ( D P \ ht|"Chapter 20- Currents and CircuitsoshapEddier ddiddiNormal MIS4SMicrosoft Word 9.0s@d@ތA@ޫx@(>=՜.+,0 hp|  OK "Chapter 20- Currents and Circuits Title !"#$%&'*Root Entry F,1TableWordDocument"SummaryInformation(DocumentSummaryInformation8 CompObjjObjectPool  FMicrosoft Word Document MSWordDocWord.Document.89q