A Beginner’s Guide to Electronic Circuit Design

Everyone has been there. You plug in your phone and wonder how the electricity gets from the power lines to your devices. Your house is wired like a circuit so that electricity can flow to all of your appliances and fixtures.

Although the circuit in your house is fairly complicated, the basics of circuit design are straightforward. Keep reading to learn all about how circuits work and an introduction to electronic circuit design from concept to implementation.

Electronic Circuit Basics

A basic circuit works by allowing electrons to flow. This is what we call electricity. When a circuit is closed, that means electrons can flow around a complete loop. Circuits must consist of conductive material but can be in a variety of shapes.

The flow of electrons is an electric current. When electrons flow in only one direction, this is direct current (DC) while a flow in different directions is alternating current (AC).

Current is measured in Amperes or Amps which measures how much electric charge flows per second. The mechanism that causes electrons to move is the voltage.

When there is a voltage or potential drop in a circuit, electrons flow from higher voltage to lower voltage. Voltage is measured in Volts after the Italian physicist Alessandro Volta.

Since no material is a perfect conductor, every component of a circuit, and even the wires in the circuit, hinder the movement of the electrons as they flow. This is electrical resistance.

Resistance is measured in Ohms and represents the voltage divided by the current in basic circuits. Electrical power is the voltage times the current and is measured in Watts.

Electronic Circuit Components

There are several basic components that go into the design of any basic circuit. Almost all circuits for practical use have these components in some form or another.

Power Source

Every circuit needs a source of power. It needs something to provide the voltage that causes the electrons to flow in the circuit. While there can be many different power sources, a simple example is a battery.

A battery uses a chemical process to create a potential difference between its two ends. Most household batteries have a voltage of 1.5 volts. This means the positive pole has a voltage 1.5V higher than the negative pole.

While batteries provide DC current, most homes and businesses run off of AC  current which power lines transmit from your local power stations.

Resistors

While every component in a circuit has some resistance, some components have the purpose of providing resistance to a circuit. These resistors limit the flow of electricity in the circuit so it can be carefully controlled.

Resistors provide a voltage drop within a circuit that must be equal to the rise in voltage that the power source provides. You can connect resistors in various ways in a circuit to get exactly the right amount of electricity where you want it.

Many things that use electricity, such as lightbulbs or appliances, act as resistors in that they draw a voltage from the circuit, causing the voltage to drop.

Simple resistors are Ohmic which means they don’t change resistance. However, most things light lightbulbs increase in resistance as the current increases. This happens because they heat up which makes it harder for electrons to flow.

Capacitors

A capacitor is a component that can store and release an electric charge. When you apply a voltage to a capacitor, charge builds up on one side which results in an electric field between the two ends of the capacitor.

When you disconnect the capacitor from the voltage source, it slowly releases the charge that had built up in a very controlled way. Capacitors allow the flow of alternating current but not direct current.

Inductors

Inductors are essentially just parts of wire that form a tight coil. When current flows through them, they produce a magnetic field which can provide a form of energy storage different from a capacitor.

Together with capacitors, inductors allow for the design of circuits that tune to a specific frequency. These are LC circuits or band-pass filters.

Diodes

A diode is an electrical component that only allows the flow of electricity in one direction. It can act as a switch to control the flow of electricity. Several diodes can be used together to form the logic gates that computers need to function.

Electronic Circuit Design

You can put together the basic components of a circuit to get various effects. There are three simple ways to connect components.

Series

Components connected in series form a chain where one end of the component connects to the other end of another component. Every component connected in series has the same current but may have a different voltage drop.

Parallel

Components connected in parallel require the electricity to split. When electricity comes from one component and splits at a junction leading to two other components, those components are in parallel with each other.

Components in parallel have the same voltage drops but may have a different current.

Combination

For more complicated circuit designs, some combination of components in series and parallel is required. There are many ways to put a circuit together to get it to do exactly what you want it to do.

A good way to start any electronic circuit design analysis is to use a computer to simulate it first. Basic electronic circuit design software will help you figure out exactly how to design the circuit you want.

If you are thinking about making your own circuit, you may need a guide for circuit design to help you.

Next Steps

Now that you know all about the basics of electronic circuit design, feel free to do some more research and try to build a circuit of your own.

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