All circuits are not created equal! Building on the previous lessons in the Crash Course series, the 29th lesson explains how electric current flows through a circuit. It spends equal time discussing both series and parallel circuits.

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Paul Andersen explains how the resistivity of a material opposes the flow of charge. [4:22]

The following video narrated by Paul Andersen explains how resistors and capacitors affect circuits. The resistance of a resistor is affected by the resistivity of the material and the geometry of the resistor. The current through a...

The following video narrated by Paul Andersen explains how electric circuits contain different elements which can be connected in series or in parallel. The following four elements are explained in detail; emf, resistor, capacitor, and...

In the video we show you how to attach spouts, sliding switches and resistors. [5:41]

Batteries power much of your daily life. In this video episode of Crash Course Physics, we're going to talk about how they work. We're also explaining how terminal voltage results from the natural internal resistance of every real...

How does Stranger Things fit in with Physics and, more specifically, circuit analysis? I'm glad you asked! In this video episode of Crash Course Physics, Shini walks us through the differences between series and parallel circuits and how...

In this video episode of Crash Course Physics, it's time to delve into the world of AC Circuits (or Alternating Currents). We've talked about how they change voltage, which helps transmit electricity over long distances, but there's so...

An example of simplifying a seemingly complicated resistor circuit. [9:44]

View an example of a basic circuit for lights. [0:32]

View a demonstration of how to wire LED lights for robot eyes. [10:33]

We use the inside of a pencil (graphite) to apply different 'lengths of pencil' to the circuit. What relationship do you observe between the length of graphite and deflection angle? Watch this video to find out! [1:27]

A pencil causes a change in the deflection, similar to the effect of adding an electromagnet. Why? Watch this video and find out! [1:04]

Here we draw a line on a page and use it as a variable resistor in series with a speaker. What relationship do we hear? Does it sound linear? Watch and find out![1:11]

Why does the deflection change when an electromagnet is attached to the circuit? Does it matter what side of the electromagnet we test? Watch this video to find out. [1:11]