Electric Current & Circuits

Understanding electric current, resistance, and how circuits work

Topics

How do batteries work?

Batteries work by converting chemical energy into electrical energy through chemical reactions. They contain two electrodes (anode and cathode) separated by an electrolyte, with chemical reactions creating voltage that drives current through circuits.

How do circuits work?

Circuits work by providing a complete path for electric current to flow from a voltage source through components and back. Current flows when the circuit is closed, powering devices and allowing electricity to do work.

How do series and parallel circuits differ?

In series circuits, components are connected end-to-end so current flows through each component sequentially. In parallel circuits, components are connected across the same voltage source so current splits among branches. Series circuits have the same current everywhere but voltage divides; parallel circuits have the same voltage but current divides.

How do transformers work?

Transformers work using electromagnetic induction—alternating current in the primary coil creates a changing magnetic field, which induces voltage in the secondary coil. The voltage ratio equals the turns ratio, allowing transformers to increase or decrease voltage while maintaining the same frequency.

What is alternating current?

Alternating current (AC) is electric current that periodically reverses direction, flowing back and forth in a circuit. Unlike direct current (DC) which flows in one direction, AC current changes direction many times per second, typically 50 or 60 times per second (hertz) in power systems.

What is electric current?

Electric current is the flow of electric charge, typically electrons moving through a conductor. It's measured in amperes (amps) and represents the rate at which charge flows through a circuit.

What is electrical energy?

Electrical energy is the energy associated with electric charges and their movement. It's the energy transferred when electric current flows through a circuit, calculated as energy = power × time or energy = voltage × charge. Electrical energy can be converted to other forms like light, heat, or mechanical work.