Electric Current

Electric Current Electric current- The flow of electrons through a wire or any conductor. Measured in units of Amperes (A) Different from static electricity because it lasts longer Charges flow from High voltage to Low voltage Voltage difference- push that causes charges to move- measured in volts (V) For charges to flow, the wire must always be connected in a closed path, or circuit

Electrical Circuits Less resistance means less heat, which is safer for use in your home Ohm’s law- current in a circuit equals the voltage difference divided by the resistance. As resistance increases, current decreases As voltage difference increases, current increases

Electrical Circuits Series circuit- current has only one loop to flow through Parallel circuit- current has more than one loop to flow through Magnetic fields form around wires through which electricity is moving Electromagnet- a temporary magnet made by placing a piece of iron inside a current-carrying loop of wire More loops = stronger More voltage = stronger Only works for DC current

Resistance All materials have some electrical resistance. Resistance is measured in Ohms (Ω) Making wires thinner, longer, or hotter increases the resistance

Electrical Circuits Circuits rely on generators at power plants to produce a voltage difference across the outlet, causing the charge to Flow when the circuit is complete Series Circuit- the current has only one path to flow through

Series Circuits

Series circuit The parts of a series circuit are wired one after another, so the amount of current is the same through every part Open Circuit- if any part of the circuit is disconnected, no current flows Example- old style Christmas lights

Voltage Source Wire- conductor Load- like a bulb Switch

Parallel Circuit Parallel Circuit- contains two or more paths for the current to move through

Parallel Circuits Individual parts can be opened without affecting the entire circuit Like the lights in your house Household circuits are parallel circuits Each branch receives 120 V from the electric company Electrical energy enters your home at the circuit breaker or fuse box and branches out to wall sockets, major appliances, and lights

Circuits Guards against overheating electric wires: Fuses- contain a small piece of metal that melts if the current becomes too high, opening the circuit and stopping the flow of current Circuit breakers- contain a small piece of metal that bends when it gets hot, opening the circuit and stopping the current