Voltage

This is the name given to the quantity of electrons in a wire relative to another wire. Electrons, like water, flow from high to low. So voltage tells you which way electrons would flow if two wires were connected.

Power & Ground

These are simply names given to voltages for convenient communication. It is convention to pick a reference net and designate its voltage as zero. All other voltages are then measured relative to this common ground voltage, for example a +5V power net is really just 5 more volts than ground.

Current

Voltage provides us with a word for the energy potential between two nodes. Its sister measurement, current, describes the amount of energy flowing through a given path in the circuit. Think of it like the amount of water flowing through a pipe.

Impedance

The resistance against the flow of electrons between two nodes in a circuit is its impedance. Impedance is an important tool in controlling voltages and currents in a circuit. You will use it to create new voltages, to limit current through LEDs, and too make sure power and ground aren’t shorted together.

Digital & Binary

Humans are much better at understanding absolute binary states (eg. on vs. off) than they are at understanding analog gradients. As a result, most electronics produced these days are digital, ie. based on binary signalling. Instead of communicating between components in analog, we do so in binary by sending patterns of high and low voltages (1’s and 0’s) which are then interpreted as commands.

Second, there are very generalized classes of components that make up most hardware products. The most important of these are the following.

Microcontrollers

These are by far the most popular active components money can buy and they allow your device to “think”. They cost as little as pennies, they enable you device to run software, and they exist in almost every electronic device you own.

Sensors

These components allow you to “listen” to the world. They can sense everything from light, to temperature, to motion and when connected to microcontrollers, and communication they allow you to listen, think, and share.

Storage

These components allow you to “record” any binary data. They come in all kind of sizes, they often connect directly to microcontrollers, sensors or communication, and they give your devices a memory.

Communication

These components allow you to “talk” with other devices. There are off the shelf devices that communicate in most of the languages you already know about (bluetooth, wireless, infrared, etc), often compared by range, bandwidth, speed and cost.

And that’s the crash course. Almost every device you ever design will involve most of these component groups and designing it will require some understanding of each of the concepts. It’s ok if it’s still all a bit fuzzy, it will get clearer. You’re now ready to move on to the ideation phase.