# Circuits IV Pt I

 Define circuit diagram  Draw the circuit diagram representations of the following: Circuit diagram: a logical picture of what is connected to what. The actual circuit may look different from the circuit diagram, but have the same logic and connections.  Draw the circuit diagram for the simple circuit shown and label the emf, R, and C of the capacitor. Also state the direction of the current   The wires, which in practice may bend and curve, are shown as ______ _______ connections between the circuit elements Current goes in a clockwise direction starting from the battery's positive terminal and ending on its negative terminal straight-line connections B. Its not connected to the negative end so its not a closed/complete circuit Explain the Junction Rule It is a statement of conservation of ______ and ______ Explain the Loop Rule  ΔVi is the potential difference of the ___ ______ of the loop.  It is a statement of conservation of _____ The potential energy ______ whenever the charge moves through the potential drop.  ΔVR for a resistor is always ________ (why?) Why do we often speak of the "voltage drop" across the resistor? ΔVbat can be negative for a battery (why?) In each diagram, ΔV = ______ and the circuit element is ______ from a to b, left to right  decreasesΔVR for a resistor is always negative because the potential in a resistor decreases along the direction of the current Because the potential across a resistor always decreasesΔVbat can be negative for a battery because the current can go through a battery in a "wrong," positive-to-negative direction when it is forced to do so by other, higher voltage batteries. ΔV = Vb - Vatraversed The potential energy _______ whenever the charge passes through a battery from the negative terminal to the positive terminal  ΔVR for a resistor increases (How is this possible?) **pg 776 increasesΔVR for a resistor is positive because the potential in a resistor increases along the direction opposite the current  Since the potential drop in an ideal wire is ______, state the formula for:  ΔVloop (4) ε (1) zero  B. junction rule: 2.5 - 1.5 = 1.0 A A. The signs for both batteries are the same and both batteries are in series, so we can combine them into one battery of ε = 7.5 VBecause all the resistors are in series ☞Kirchhoff's Law: Loop RuleΔVloop = ΔVbat + ΔVR1 + ΔVR2 + ΔVR3 = 0ΔVloop = ε + ΔVR1 ΔVR2 + ΔVR3 = 0(7.5 V) + (-3.0 V) + (-ΔVR2) +(-2.5 V) = 02.0 V = ΔVR2 **Note: If the symbols for the batteries were opposite it would be 4.5 V - 3.5 V = 1.5 V and the 4.5 V battery would still be the dominant battery, so it would still dictate the direction of the current E. The dominant battery (9 V) dictates the direction of the current which will be clockwise. However, that current passes through the 6 V battery from + to - instead of - to +, so the current it will be a voltage drop: 9 V - 6 V = 3 VOHM's Law:I = ΔV/R I = (3.0 V)/(3 Ω) = 1 A Low to high soε - IR1 - IR2 = 0 ε = +12V and IR1 = I(12) and IR2 = I(6) 12 - 18I = 0I = 18/12 = 2/3 So D. A circuit with multiple elements can have different ways of connecting them.  Two basic ways of connection (name and draw them) When two or more elements are connected end-to-end, they are said to be in a ______ _______. There is NO _______ in between. Each element receives the same amount of _______ passing through it, but with different _______ across. series combination junctioncurrent potential  Same current pass through each resistors Applying Kirchhoff's loop law:  ___ - ___ - ___ = 0 ε = ___ + ___ We can replace two resistors with a single resistor having the value Req = R1 + R2 The potential difference across the battery is also applied to the ________ ________ (___):  ε = _____ The equivalent resistance has the same effect on the circuit as the ______ _______ (why?) equivalent resistance (Req):ε = IReqseries combination because it results in the same current (I) in the battery The equivalent resistance of three or more resistors connected in series is:  Req = ? The equivalent resistance of a series combination of resistors is the numerical sum of the _______ _________ It is always ________ than any individual resistance Req = R1 + R2 +R3 +...individual resistancesgreater In a circuit with one bulb, a battery drives the current IA = ____ through the bulb A. In a circuit with two bulbs in series with the same resistance R, the equivalent resistance is Req = ___ The current running through the bulbs is: IB = ____ = ____ Since the emf is the same for both circuits,  IB = ____ Thus, bulb B & bulb C are _____ bright, but they are ______ than bulb A because there is _____ current IA = ε/RReq = 2RIB = IC = ε/2RIB = 1/2(IA)equally brightdimmer less **Note: Bulbs of the same complete circuit are of the same current and hence brightness. All things equal, A should be brighter than B and C The Christmas bulbs are not in series, maybe every 3 or 4 bulbs are but not all of them A battery is a source of ______ ______, not a source of _______.  The battery does provide the current in a circuit, but the amount of current depends on the _______.  The amount of current depends jointly on the ________ ______ and the ________ of the circuit attached to the battery potential difference currentresistancebattery's emf and resistance Consider two resistor in a parallel combination: Both resistors are connected directly across the terminals of the battery  The potential difference across the resistors are ____ _____:  ΔV = ____ = ____ ΔV is the ______ ______ of the battery the same ΔV = ΔV1 = ΔV2terminal voltage  When charges reach a junction, the current splits into two parts, with some going toward R1 and the rest going toward R2 Define Junction Junction: any such point in a circuit where a current can split  This split results in _____ current in each individual resistor than the current leaving the battery. The current (I) that enters point a must equal the total leaving that point:  I = ______ = ______ = _______ I1 is the current in R1 and I2 is the current in R2 less The current in the equivalent resistance Req is:  I = ___ = ___ The equivalent resistance has the _____ _____ on the circuit as the two resistors in parallel The equivalent resistance draws the same ______ from the battery I = ΔV/Req =  ε/Reqsame effect current (I) The equivalent resistance of 3 or more resistors in parallel is given by:  1/Req = ? The inverse of the equivalent resistance of two or more resistors in a parallel combination is equal to the sum of the _______ of the individual resistances. The equivalent resistance is always ______ than the smallest resistance in the group Parallel resistors provide more _______ for charge to get through An analogy is driving in heavy traffic (explain). inverses lesspathwaysIf there is an alternate route for cars (current) to travel, more cars (current) will be able to flow freely Authorchikeokjr ID346833 Card SetCircuits IV Pt I DescriptionCircuits IV Pt I Updated2019-05-10T22:22:46Z Show Answers