For week three go over electron flow and conventional flow. Electrons only flow in one directions. Units to be measured and calculated VoltageVoltsV or E ResistanceOhmsR or Current AmpsI or A There can be voltage without current but not current without voltage. There can be resistance without current or voltage. Current may or may not be present in a circuit. Current is through out the circuit. Meter Dos and Donts Short the leads of the meter to verify it is working and to see how a short is indicated (voltage and resistance). Do not make resistance measurements with power connected. Voltage is measured across a device in question. It must be on opposite ends or sides. Voltage is a specific measure of potential energy that is always relative between two points. Page 35 Two electrically different points. V source V AB V BA Resistance is measured across a device in question. It must be on opposite ends or sides. R or Voltage sources must be removed. Current must be measured by opening the circuit and putting the meter in line or in series so that the current passes through the meter. A or I Multisim Place Source = DC Power and Ground Place Basic = Resistors Giga Micro V source = V R = V AB I source = I R = I A Week 2 day 2 work sheet What would the voltage be between points A and D? What would the voltage be between points B and C? What would the voltage be between points A and B? What would the voltage be between points D and A? Week 2 day 2 work sheet What would the voltage be between points A and D? What would the voltage be between points B and C? What would the voltage be between points A and B? What would the voltage be between points D and A? COLOR CODING FOR RESISTORS COLOR CODING AND STANDARD RESISTOR VALUES Ground or Common Unless otherwise noted the common lead of the meter is connected to the ground or common point of the circuit. Ground or common is usually associated with the negative terminal of a DC power supply. Important concepts from chapter 2. Page 50 Any device that performs some useful task with electric power is generally known as a load. Load in a circuit diagram is explaining some concept unrelated to the actual use of electrical power. 2.7 Circuit wiring page 57 Connecting wire resistance is little or none, we can regard the connected points in a circuit as being electrically common. 2.7 Circuit wiring page 57 Points 1 and 2 or 3 and 4 in the above circuits may be physically joined together or apart, it doesnt matter for any voltage or resistance measurements. 2.7 Circuit wiring page 57 It is as if the ends of the resistor were attached directly across the terminals of the battery. Which points have something between them? 2.8 Polarity of voltage drops page 60 The author is using electron flow. Which points have something between them? Page 61 Polarity has nothing to do with Ohms Law: there are no negative voltages, currents, or resistance entered into any Ohms Law equations! There are other principles of electricity that do take polarity into account. Page 48 Because they are simple and so commonly used well spend a considerable amount of time analyzing circuits composed of nothing but resistors and batteries. 2.6 Nonlinear conduction Page 53, 54, 55, 56 not needed for what we are doing. Quote from author: I just wanted to expose you to a little bit of the complexity of the real world, lest I give you the false impression that the whole of electrical phenomena could be summarized in a few simple equations. 2.9 Computer simulation of electric circuits pages We will be using National Instruments, Multisim. You do not need to read section 2.9 Ohms Law page 40 Page 39 It is used so often in the study of electricity and electronics that it needs to be committed to memory. White board exercise Units to be measured and calculated VoltageVoltsV or E ResistanceOhmsR or Current AmpsI or A PowerWattW or P 2.3 Power in electric circuits We wont be using this. Page 42 2.3 Power in electric circuits We will be using this. Page 43 Watt W or P Units to be measured and calculated VoltageVoltsV or E ResistanceOhmsR or Current AmpsI or A