October 28, 2020

Basic Circuit Board Components And What They Do

Circuit boards are found in most of the devices that we use on a daily basis. However, most peopl do not know what components are used to create these circuit boards and what these components do.  It is important that you know what circuit board components are used and what they add to the board.


One of the most common components in a circuit board is the resistor.  The resistor is used on the circuit board to control the current and voltage that flows through the circuit.  The resistor will help to reduce the chances of a burn out which is very important when dealing with circuit boards.

There are 2 reasons why resistors are included in circuits and they are to limit current and to divide voltage.  When you are limiting current, you will need a resistor to comply with Ohm%u2019s law.  This law states that when the voltage remains the same, it will only decrease when met with resistance.

Dividing voltage with a resistor is actually a different form of limiting the current.  When doing this, you will be using a resistor to decrease the voltage to a level that is appropriate for the next component.  This means that if your circuit is powered by a 3-volt battery and you need to reduce this to 1.5 volts for a part of your circuit, you will install 2 resistors of equal value.

It is important to note that resistors come in a range of different shapes and sizes.  It is important that you know which type of resistor you need for the circuit that you are working with.  If you are completing a hobby electronics circuit, you will need to look at a carbon film resistor.


Capacitors are very simple components and will consist of 2 parts.  The first is the electrical conductor also known as plates which will be separated by the second part which is the insulator known as a dielectric.  There are 2 functions that capacitors complete when in a circuit and they are to store electrical energy and to create a timer.

Capacitors are able to store electrical energy as they work like a temporary batter.  When the current runs through the capacitor, it will be stored and then fed to the other components in the circuit.  This is ideal for the parts of the circuit where there are no other voltage sources.

When you pair the capacitor with a resistor, you will be able to create a timer on the circuit board. When this happens, the capacitor will be able to control the amount of time it takes for an event such as a buzzer sounding to happen.


The diodes that you find in circuit boards will be a small device that allows the current to flow in only one direction.  Each diode will have 2 terminals called the anode and cathode.  The diode will only operate when positive voltage flows into the anode and negative voltage flows to the cathode.  If the voltage is the other way, the diode will not work, and the current will not flow through it.

There are a number of different types of diodes with the most commonly known being the light emitting diode or LED.  Light emitting diodes are often used in circuit boards to indicate when the current is running through them or when certain parts of the circuit are active.  As the name suggests, these diodes will emit a light when the current runs through them correctly.


The transistor that you generally find in a circuit board will be a device that has 3 terminals.  The voltage in the circuit will be applied to the first terminal known as the base.  This terminal will control the current which flows across the other 2 terminals of the transistor known as the collector and the emitter.  This makes the transistor one of the most important components in any circuit board.

There are many different types of transistors that you need to know about.  The most basic will be the bipolar transistor while others are known as the field-effect transistor which is becoming more popular.  The bipolar transistor is the easiest to use and understand and is commonly used by hobby electronic users.

The bipolar transistor will have 2 current paths which can be used.  The collector-emitter path will be the primary current that flows through the transistor.  The voltage will be placed across the collector and the emitter.

The base-emitter flow will be the current path that controls the flow of current through the collector-emitter path.  This is actually the first flow of current into the transistor and current will not be able to flow out of the base terminal.


The last basic circuit parts in a circuit board will be the inductor.  This is a coil which has been designed for use in these circuits and will take advantage of the self-inductance afforded to coils.  The inductor is actually a very simple device and will consist of only a coil of wire which is wrapped around an iron core.

When voltage is applied to the coil, the current will start to flow through it.  The current which flows through the coil will create a magnetic field around the coil.  If the flow of current through the coil changes, the magnetic field which has been created will also change. The magnetic field will grow and shrink according to the amount of current that is flowing through the coil.

As the magnetic field is moving, the coil will induce voltage.  This voltage will be additional voltage over and above the initial voltage that was provided by the main current into the coil.  The amount of voltage that is created will vary depending on the speed of the current changes.  When the current changes are fast, more voltage will be induced.

There are many different components that make up a basic electrical circuit board.  It is important that you know what these components are as well as what they actually do.  This will help you better understand any circuit boards that you are going to work with.