Physics I Honors 1 Current and Circuits Circuits Schematics Use of Meters
Physics I Honors 2 Objectives Describe the utilization of ammeters and voltmeters in circuits. Describe the utilization of fuses and circuit breakers in protecting electrical circuits
Physics I Honors 3 Circuit Defined A circuit is a path for electrons to flow through. The path is from a power source’s negative terminal, through the various components and on to the positive terminal –Types Series Parallel Combination
Physics I Honors 4 Components - Source DRY CELL a source of electrical energy + + - -
Physics I Honors 5 Components - Load LIGHT BULB lights up when electricity pass through
Physics I Honors 6 Circuit - Complete Source of electrical energy + + - -Appliances Complete circuit Electricity flows
Physics I Honors 7 Terms to Know Open circuit – there is a break somewhere and electricity cannot flow (maybe the switch is open) Closed circuit – electricity can flow (the switch is closed) Short circuit – the electricity completes a circuit without going through the load Load – what is using the electricity
Physics I Honors 8 Schematics Circuit diagrams, also called schematic diagrams, provide a graphic representation of an electric circuit using standard symbols.
Physics I Honors 9 Diagram Symbols wire or conductor resistor or other load bulb voltmeter battery ammeter switch generator V A
Physics I Honors 10 The Ammeter This device measures current. It is a Galvanometer wired in parallel to a resister (shunt). Ammeters are connected in series to the circuit.
Physics I Honors 11 The Voltmeter This device measures electric potential…voltage. It is a Galvanometer wired in series with a resistor (a multiplier.) Voltmeters are connected in parallel to the load
Physics I Honors 12 Fuses and Shorts If an electric circuit gets “overloaded” (too much current!) fuses or circuit breakers interrupt the flow of current. Too many devices can require more current than the wires can handle -- overheating of wires is a fire hazard !!! Fuses Circuit Breaker
Physics I Honors 13 Example – Simple Circuit circuit diagram + - A +- A
Physics I Honors 14 Complex Circuit Construct the circuit diagram + - A +- A