Physics Electricity Fundamentals

Understanding electricity starts with electric charges - they're like invisible forces that either pull together or push apart. Opposite charges attract each other (like magnets), whilst same charges repel each other. When objects lose electrons, they become positively charged, and when they gain electrons, they become negatively charged.

The magic happens when charges move around circuits using four key measurements. Current measures how fast electric charge flows (like water through a pipe), measured in amperes (A). Voltage (or potential difference) is the electrical 'push' that forces current through resistance, measured in volts (V). Resistance measures how much a material fights against the flow of electricity, measured in ohms (Ω).

Power tells us how much energy is used per second, measured in watts (W). You can calculate it by multiplying current and voltage together. These concepts work together - potential difference pushes current through resistance to make electrical devices work.

Quick Tip: Remember VEIR - Voltage pushes, Electric current flows, through Resistance!

Circuit components each have specific jobs and symbols. Resistors limit electron flow, whilst diodes only allow current to flow in one direction. Ammeters measure current and must be connected in series, whereas voltmeters measure voltage and connect in parallel. Special resistors like LDRs (Light Dependent Resistors) change resistance with light levels, and thermistors change resistance with temperature.

Series circuits share voltage between components but have the same current everywhere - resistances add up for total resistance. Parallel circuits have the same voltage across each branch, but currents add up, making total resistance less than the smallest branch resistance.