I forgot my username or password.

In support of all the students who are displaced from school due to the Corona virus. Access to physics zone and chemistry zone lessons are now available free of charge. This will be maintained at least through August 1st 2020. Learn and be well.

Physics Lessons Review Links Solutions Physics Shop

The Simple Circuit

A simple circuit contains the minimum things needed to have a functioning electric circuit. A simple circuit requires three (3) things:

  1. A source of electrical potential difference or voltage. (typically a battery or electrical outlet)
  2. A conductive path which would allow for the movement of charges. (typically made of wire)
  3. An electrical resistance (resistor) which is loosely defined as any object that uses electricity to do work. (a light bulb, electric motor, heating element, speaker, etc.)

Despite being considered simple, they are useful and quite common. They exist as flashlights, doorbells, and many kitchen appliances. From a Physics point of view they display many of the rules that govern the behavior of electricity in circuits. Below is an animation of a simple circuit where electrical energy is shown as gravitational potential energy (GPE).

In this animation you should notice the following things:

Ohm's Law describes mathematically the relationship between current and voltage (potential difference). The more potential difference you have the greater your current is going to be. The more resistance a circuit has, the lower the current is going to be. The following equation is Ohm's Law. It holds true for any circuit as long as temperature does not change.