ELECTRIC CURRENT The current to be measured must pass directly through the ammeter. This means that the ammeter is connected in SERIES in the circuit. Electric Current Current: a measure of the rate of electron flow past a given point in a circuit -measured in amperes (A) Simplest Definition: # of electrons(passing through) a specific point LG: to understand electric current at a basic level Ammeter: device used to measure electric current -has to be connected in series to count all electrons LG: to understand electric current at a basic level Electric Current Reading Meters: the scale used depends on the connection you attach the wire to. -determine the value of each mark between numbers -estimate the last digit between marks LG: to understand electric current at a basic level Electric Current LG: to understand electric current at a basic level Electric Current Amperage = ? LG: to understand electric current at a basic level Electric Current Amperage = 12.38 A LG: to understand electric current at a basic level Electric Current Amperage = ? LG: to understand electric current at a basic level Electric Current Amperage = 21.7 A LG: to understand electric current at a basic level Draw a schematic diagram of a circuit containing 3 light bulbs connected in series, 2 cell battery, motor and an ammeter measuring current. Show current flow.. Safety with Electric Currents: large currents can damage electrical devices, cause fires and harm you Fuses & Circuit Breakers: open the circuit if current flow is too high -placed in series with everything else on the circuit LG: to understand electric current at a basic level Fuse A safety device that opens a circuit if the current gets too high. It must then be replaced. LG: to understand electric current at a basic level Circuit Breakers A safety device that opens a circuit if the current gets too high. It can be reset. GFCI outlets • is a device that shuts off an electric power circuit when it detects that current is flowing along an unintended path (water or a person). • It is used to reduce the risk of electric shock or fire. Grounding terminals • Allows excess current to flow in to the ground instead of giving you a shock. Electrical Shock: the brain and nervous system send messages using electrical signals -even small amounts of current are dangerous 0.0050 – 0.0150 A: muscles contract or convulse out of control 0.015- 0.05: called "let go" threshold because beyond that current a person can no longer let go of the object shocking them 0.05 – 4.3 A: will stop the heart 15 A: the amount of current from a wall outlet
