While cooking the other day, I realized my family had about 40 different spices and seasonings in our cupboard. I regularly cook with about 10 or so. My wife, who is more of a baker, uses about 30 or so. As a chef, that’s a lot of input ingredients and complexity to consider. Yet, we are generally not intimidated by cooking and we all do it.
Turns out, when considering the complexity of input ingredients, circuit design is way simpler than cooking. Unlike cooking ingredients, circuit designers use effectively 6 fundamental components - that’s right SIX - to build and design any modern day tech gadget of any variety.
(Top left to right: resistor, capacitor, inductor, diode, transistor. Bottom: wire)
Wire - this is what you use to connect components together. It is also the fundamental building block for something like a light bulb which is effectively a very fine piece of wire (ie filament) that emits light and heats up when electric current flows upon a flick of the switch.
Resistors - as its name suggests a resistor resists electric current. Like how a river dam controls and limits water current flow down the river, the resistor limits the amount of electric current flowing through our circuit. As an example, by controlling electric current, we can limit how bright an light bulb shines.
Capacitors - this component stores and provides electric energy much like a water reservoir can store and provide water when needed. Sometimes voltage drops because your battery or wall outlet is not a perfect source of electric energy and on occasion the voltage can drop temporarily - say when the vibrating motor on your phone kicks on. During this moment of voltage drop, the capacitor can make up the temporary loss to prevent your phone from resetting. Additionally, without diving into detail, a capacitor’s ability to store electricity makes it an essential component to convert the alternating current (AC) from your wall outlet to a stable direct current (DC) needed to say, charge your cell phone.
Inductors - this component also stores electric energy but in the form of a magnetic field. It is the fundamental building block for an electro-magnet, which is the building block for an electric motor.
Diodes - in a wire, electric current can flow in either direction - from one end or the other. Such is the case with alternating current (AC) coming out of your wall socket - current is moving back and forth. Simply speaking, a diode is a one way traffic officer that allows electric current to only flow in one direction. Combined with a capacitor and resistor, you have a circuit that can convert AC to DC - a circuit in every wall adapter you own. Additionally, diodes have another amazing property for a totally different yet pervasive application. When electric current passes through a diode, the diode can emit light which is the fundamental property of light emitting diodes better known as LED’s.
Transistors - due to similarities in construction, a transistor is a cousin to diodes. While diodes directs electric current to only flow in one direction, transistors can control when/if electric current can flow through. In other words it’s a switch. For a mechanical switch, like a wall switch, when it’s on, the switch closes the circuit and electric current can flow through the switch. The switch toggle is mechanical - meaning, you physically need to turn it on or off.
For a transistor, the toggle is electrical. Depending on the voltage applied to its electric toggle, the transistor switch turns on or off. Imagine a transistor switch that controls if/when another transistor switch turns on/off, that controls another transistor switch and so on. That chain or topology of how the transistor switches wire together in a circuit define it’s functionality. Does the circuit implement a simple calculator, timer? Or perhaps this circuit (of millions of transistors) implements a modern central processing unit (CPU) in a computer or smartphone.
With these 6 components, you can create anything from a simple light circuit to a modern day computer.
With EEME, your family will use all them to build the various projects. And we'll dive deeper into how they work.
If you don’t view cooking as a monumental skill, then you have no reason to be intimidated by circuit design.
Happy building! Jack "EEME Dad"