Electric Circuits

Circuit / Water Analogy

A simple DC circuit has a DC voltage source lighting a light bulb. Also shown is a hydraulic system in which water drives a turbine. The two systems are shown to be similar.

Battery Voltage

Look inside a battery to see how it works. Select the battery voltage and little stick figures move charges from one end of the battery to the other. A voltmeter tells you the resulting battery voltage.

Battery Resistor Circuit

Look inside a resistor to see how it works. Increase the battery voltage to make more electrons flow though the resistor. Increase the resistance to block the flow of electrons. Watch the current and resistor temperature change.

Ohm's Law

See how the equation form of Ohm's law relates to a simple circuit. Adjust the voltage and resistance, and see the current change according to Ohm's law. The sizes of the symbols in the equation change to match the circuit diagram.

Resistance in a Wire

Learn about the physics of resistance in a wire. Change its resistivity, length, and area to see how they affect the wire's resistance. The sizes of the symbols in the equation change along with the diagram of a wire.

Signal Circuit

Why do the lights turn on in a room as soon as you flip a switch? Flip the switch and electrons slowly creep along a wire. The light turns on when the signal reaches it.

Light Switch A simple animation of how a common light Switch works.
Circuit Construction Kit (DC)

An electronics kit in your computer! Build circuits with resistors, light bulbs, batteries, and switches. Take measurements with the realistic ammeter and voltmeter. View the circuit as a schematic diagram, or switch to a life-like view.

Combinations of Resistors
This applets allows the user to create series and parallel combinations of resistors and measure the resulting current.
Simple Buzzer A simple buzzer consisting of a battery, a flexibile metal strip, a piece of iron, and some wire.
Charging and Discharging a Capacitor
This applets shows an animation of a capacitor that is charging or discharging. Use the mouse cursor to control the Switch Position slider, and discover how a capacitor is charged and discharged with current from the battery.
Lightning - a Natural Capacitor
This applets shows an animation of how lightning is formed and explains how lightning is an example of a natural capacitor.
RC Circuit
This applet allows the user to set the resistance and capacitance of a simple RC Circuit. The applet plots the voltage across the capacitor and the current in the circuit.
RC Circuit

RC Circuit models the dynamical behavior of a voltage source attached in series to a resistor and capacitor. The source voltage can be chosen to be either a 10 volt sinusoidal or square wave with an adjustable frequency.

The downloadable Java Applets were taken either from PhET or Open Source Physics.

The Flash Animations were all taken from David M. Harrison from the University of Toronto.