Baker's A&P Oral and practical Study Guide General section

Baker's A&P Oral and practical Study Guide General section What is the most important law applicable to the study of electricity? - Ohm's Law (V = I x R) What are the elements of Ohm's Law? - Voltage (v), Current (I), Resistance (R) What are 4 sources of electrical power? - Mechanical (generator/ alternator), Chemical (battery), Photoelectric (light), and Thermal (heat) What does an electrical circuit consist of? - A source of electrical pressure (EMF), Resistance in the form of an energy consuming electrical device(light bulb), Conductors to provide a path for electron flow (wires). (a Power source, a load, and a conductor connecting the load and the power source) What represents capacitance in an AC circuit? - A Capacitor What is the function of a capacitor? - To store electricity What is Inductance? - When voltage is induced by magnetic flux lines in a coil in an AC circuit. The induced voltage is opposite in direction to the applied voltage, and opposes any change in the alternating current. What is impedance? - The total opposition for AC to flow caused by the combined effect of resistance, inductive reactance, and capacitive reactance in an AC circuit. What is the unit of measurement of power in a DC circuit? - The Watt. amp x volt = watt, how many watts are in 1 horsepower? - 746 watts What is a kilowatt? - 1000 watts In a DC circuit, what occurs when voltage is increased, while the resistance remains the constant? - There will be an increase in current What are the 3 types of DC electrical circuits? - They are Series circuits, Parallel circuits, and complex circuits (series-parallel) A 24 volt lead-acid battery has how many cells, and what is each cell rated at? - It has 12 cells, and each cell is rated at 2 volts What should be the specific gravity of the electrolytes in a fully charged lead acid battery? - It should be between 1.275 and 1.300 What instrument is used to determine the specific gravity of electrolyte in a lead acid battery? - a Hydrometer What can a hydrometer not be used to determine the charge of a nickel cadmium battery? - The specific gravity of the electrolyte in a nickel cadmium battery does not change appreciably during charge or discharge of the battery. When using a hydrometer to check the charge of a lead acid battery, at what temperatures must a correction factor be applied to the reading? - Adjustments must be made if the temperature of the electrolyte is above 90° F or Below 70°F What is electromagnetic induction? - It is the transfer of electrical energy by means of a magnetic field (lines of flux). Transferring voltage from one conductor to another without physically touching What is the principle of a transformers operation? - electromagnetic induction