Intro to Current Electricity (Notes) PDF

Current Electricity es are not useful for operating Static charg electrical devices. They build up and discharge, but they do not flow continuously. To operate electrical devices we need a steady flow of è A flo...

Current Electricity es are not useful for operating Static charg electrical devices. They build up and discharge, but they do not flow continuously. To operate electrical devices we need a steady flow of è A flow of è will more continuously as long as 2 conditions. are met: The flow of è requires an energysource The flow of e é requires a complete path to travel through. The path that & travel through The continuous flow of é is called an electrical circuit in a circuit is called Current electricity Electrical Circuits. A circuit includes (at a minimum) an energy source, a Conductor, and a load An electrical device that converts. electrical energy into another form of Many circuits also energy ex A light bulb converts electrical Include a switch to turn energy into light (and heat) the circuit" on or "off" In a circut, a switch can either be "open" or "Closed" "1 an open switch means the circuit is incomplete and è CANNOT flow : the load will be off a closed switch means the circuit is complete and e- CAN flow :. the load will be on l i gh tof ex a basic ot h e electrical load energy source electrical bulb Circuit >conducting wires switch this is an "open"switch Electrochemical Cells An electrochemical cell is a package of Chemicals that converts The chemical energ chemical energy into electrical energy. y is stored in charged particles (ions). A battery is a combination of electrochemical cells. A Simple electrochemical cell includes an electrolyte and two electrodes liquid (or paste) metal Strips that are in that conducts Contact with the electrolyte; electricity because typically made from 2 different it contains ions. metals The reaction that occurs between the electrodes and the ions in the electrolyte causes é to build up on one of the electrodes (this electrode becomes negative). The otter electrode loses è (so it becomes positive) Potential Difference aka Voltage Each é in a circuit has potential energy benergy stored in an object A battery has chemical potential energy in the electrolyte in the form of ions. The ions in the electrolyte react with the electrodes which causes one electrode to gain è, so it becomes negative (called the anode) and causes the other electrode to lose è So it becomes positive (called the cathode) So, if a conductor (like copper wire) is connected to both electrodes, the é flow from the negative anode to the positive cathode. The difference in electric potential energy between 2 points. in a circuit is called potential difference OR voltage(V) Measuring Potential Difference/Voltage. Must be measured between 2 points in a circuit using a device called a voltmeter. The unit of measure for potential difference/voltage is Volts (V) Current Electric current is a measure of the number of e- that pass by a point in a circuit each Second. The Symbol used to represent current is I The flow of current from a battery is called direct current (DC) because it flows only in one direction. But, the Current that flows from a wall outlet is Called alternating current (AC) because it flows back and forth. Measuring Current is measured using a device called an ammeter. The unit of measure for current is the ampere or often shortened to amps (A) Resistance, R The degree to which a substance opposes the flow of è All Substances resist è flow to some extent have very low resistance, so è pass through Hem easily have high resistance, so é have difficulty passing through them. When a substance resists the flow of é, it slows the current and converts electrical potential energy into other forms.  Measuring Resistance. Resistance (R) can be measured using a device called an ohmmeter, but it is not usually measured , rather it is calculated using Ohm's Law. The unit of measure for resistance is the lohm R Series ys Parallel Circuits. Different types of electrical devices require different types. of circuits. The simplest circuit is a loop. A single path for è to travel through. This is This is called a series circuit, Series circuits are used for simple electrical devices. A simple loop isn't always the best design when there are a variety of different loads in a circuit So, more complex electrical devices have circuits containing multiple loops so Here are multiple paths for é to travel through. This is a parallel circuit. Circuit Diag rams The components and connections in a circuit are illustrated using special symbols. These symbols make it easier to plan. and analyze a circuit A diagram made with these symbols. is called a circu circ it diagram OR a Schematic diagram uit Circuit Diagram Symbols. Wire Conductor; allowsc to flow through circuit. electrical # battery + power two AC power Sources batteries (wall outlet)  OR -- lamp/lightbulb convertselectricity to light loads. buzzer Converts electricity to Sound Speaker. M motor converts electricity to motion L load genericload in the circuit (use this symbol for loads other than those mentioned above) ww W resistor alternative Symbol for generic load. open switc h circuit is "off"/ incomplete. closed switch circuit is "on"/complete fuse/circuit breaker protection for a circuit V Voltmeter used to measure voltage. wired in parallel around device being measured A ammeter used to measure current. wired in series to the device being measured Series Circuit An electrical circuit in which the components are arranged one after another in series. It only has one path for the é to travel through. If this one path is disrupted, the whole circuit cannot function e + 2 batteries in Series are powerin ex g 9 Series of 2 light bulbs. and a speaker. The voltage through the speaker include being measured. a voltmeter. e- Parallel Circuits An electric circuit in which the components are arranged flow al So that è can flow along more than one path A disruption in one path does not affect the other paths in the circuit +|1|1/12 e + ex 3 batteries in series are controlling 2 light bulbs that are wired é in parallel to each other. 0 There is a Switch controlling each light bulb individually; é one bulb is on, but the other is off. The current is being He é drawn in t measured in the bulb that is on brange are no include an ammeter because moving the switch is open Combination Circuits Some circuits are combinations of both series and parallel components éé t ex A Series of 2 batteries. is powering 3 light bulbs 2 light bulbs are in light bulb ē Series and I is in parallel to one of the series bulbs. There is one Switch that controls. all the bulbs at once