Direct Current

DC Electricity Key Concepts:

Current and Voltage
Circuit diagrams: Series and parallel circuits
Ohm's Law: current, voltage and resistance
Power (and Electric Energy)

Water analogy

Electricity flow can be compared to water flow - if pressure (voltage) is applied at one end of a pipe (wire or conductor), then water (electricity) will flow out the other end (current).

JAVALAB simulation: Ohm's Law

Current

An electric current is the rate of flow of electric charge past a point or region. There are two types of currents to consider:

Conventional Current: This flows in the same direction as the movement of positive charge.
Electron Current: This flows in the opposite direction to conventional current, corresponding to the actual movement of electrons.

Electric Circuits

Basics of the voltage and current laws in series and parallel circuits.

Can you summarise them after watching the video?

Current

Cognito - 2:35

Voltage

Cognito - 4:05

Series Circuits

Cognito - 6:00

Parallel Circuits

Cognito - 3:30

Current vs. Voltage?

How Much Current Can Kill You?

Science ABC - 5 min

Which is the Killer?

ElectroBOOM - 3 min

Ohm's Law

Resistance

Electrical resistance is a property of a material that impedes the flow of electric current. The unit of resistance is the ohm (Ω).
When a voltage of 1V is applied, the conductor's resistance that allows a current of 1A is 1Ω.
When the voltage is constant, the current flowing through the circuit is inversely proportional to the electrical resistance. In other words, when the electrical resistance becomes 2 times, 3 times, 4 times..., the current becomes 1/2, 1/3, 1/4... In this way, the current flowing intensity through the wire becomes smaller as the electrical resistance increases.

Ohm's Law Explained

The Engineering Mindset - 10:00

Ohmic vs. Non Ohmic

ElectronicsNotes - 4:45

Ohm's Law

Phet - interactive animations

https://phet.colorado.edu/en/simulation/ohms-law

Resistance in Series and in Parrel

In a parallel circuit,

The current splits up when it comes to a branch. The current in all the branches adds up to the current in the main part of the circuit.
If one bulb breaks, the bulbs in the other branch stay on.
If you add more bulbs, each bulb stays bright. It is easier for electrons to flow because there are more pathways for them to follow.

In a serial circuit,

The current is the same everywhere.
If one bulb breaks, all the others go off.
If you add more bulbs, they will be dimmer because it is harder for the electricity to get through - the resistance of the circuit is higher.

JavaLab Animation

Resistance Connection - Resistance is analogous to a toll-gate, meaning that it limits the flow of current.
Serial Parallel Circuit 3

Crash Course on Electricity

Electric Current

So, electric current works like a river... kinda... Instead of flowing based on elevation, electric current works a little differently. But it's a good metaphor. In this episode of Crash Course Physics, Shini talks to us about electric current, voltaic cells, and how we get electric charge.

DC Resistors & Batteries

Batteries power much of your daily life, so today 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 battery. We'll get into both series and parallel circuit configurations, and how the laws of conservation affect the current and voltage for each.

Circuit Analysis

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