# Basic Electronics

# Breadboard

Breadboards are an essential tool for prototyping and building temporary circuits. These boards contain holes for inserting wire and components. Because of their temporary nature, they allow you to create circuits without soldering. The holes in a breadboard are connected in rows both horizontally and vertically as shown below.

# Digital Multimeter

A multimeter is a device that’s used to measure electric current (amps), voltage (volts) and resistance (ohms). It’s a great for troubleshooting circuits and is capable of measuring both AC and DC voltage. Check out this post for more info on how to use a multimeter.

multimeter basic electronics

# Test Leads (Alligator Clips)

Test leads are great for connecting components together to test a circuit without the need for soldering.

# Wire Cutter

Wire cutters are essential for stripping stranded and solid copper wire.

# Screwdriver Set

screwdrivers are also known as jeweler’s screwdrivers and usually come as a set. The advantage of these over normal screwdrivers is the precision tips of each driver. These are very handy when working with electronics that contain tiny screws.

# Heat Gun

A heat gun is used to shrink plastic tubing known as heat shrink to help protect exposed wire. Heat shrink has been called the duct tape of electronics and comes in handy in a wide variety of applications.

# Jumper Wire

These wires are used with breadboard and development boards and are generally 22-28 AWG solid core wire. Jumper wires can have male or female ends depending on how they need to be used.

# Soldering Iron

When it time to create a permanent circuit, you’ll want to solder the parts together. To do this, a soldering iron is the tool you would use. Of course a soldering iron isn’t any good unless you have solder to go with it. You can choose leaded or lead-free solder in a few diameters.

# Electronic Components

Now its time to talk about the different components that make your electronic projects come to life. Below is a quick breakdown of the most common components and functions they perform.

# Switch

Switches can come in many forms such as pushbutton, rocker, momentary and others. Their basic function is to interrupt electric current by turning a circuit on or off.

# Resistor

Resistors are used to resist the flow of current or to control the voltage in a circuit. The amount of resistance that a resistor offers is measured in Ohms. Most resistors have colored stripes on the outside and this code will tell you it’s value of resistance. You can use a multimeter or Digikey’s resistor color code calculator to determine the value of a resistor.

# Variable Resistor (Potentiometer)

A variable resistor is also known as a potentiometer. These components can be found in devices such as a light dimmer or volume control for a radio. When you turn the shaft of a potentiometer the resistance changes in the circuit.

# Light-Dependent Resistor (LDR)

A light-dependent resistor is also a variable resistor but is controlled by the light versus turning a knob. The resistance in the circuit changes with the intensity of the light. These are often found in exterior lights that automatically turn on at dusk and off at dawn.

# Capacitor

Capacitors store electricity and then discharges it back into the circuit when there is a drop in voltage. A capacitor is like a rechargeable battery and can be charged and then discharged. The value is measured in F (Farad), nano Farad (nF) or pico Farad (pF) range.

# Diode

A diode allows electricity to flow in one direction and blocks it from flowing the opposite way. The diode’s primary role is to route electricity from taking an unwanted path within the circuit.

# Light-Emitting Diode (LED)

A light-emitting diode is like a standard diode in the fact that electrical current only flows in one direction. The main difference is an LED will emit light when electricity flows through it. Inside an LED there is an anode and cathode. Current always flows from the anode (+) to the cathode (-) and never in the opposite direction. The longer leg of the LED is the positive (anode) side.

# Transistor

Transistor are tiny switches that turn a current on or off when triggered by an electric signal. In addition to being a switch, it can also be used to amplify electronic signals. A transistor is similar to a relay except with no moving parts.

# Relay

A relay is an electrically operated switch that opens or closes when power is applied. Inside a relay is an electromagnet which controls a mechanical switch.

# Integrated Circuit (IC)

An integrated circuit is a circuit that’s been reduced in size to fit inside a tiny chip. This circuit contains electronic components like resistors and capacitors but on a much smaller scale. Integrated circuits come in different variations such as 555 timers, voltage regulators, microcontrollers and many more. Each pin on an IC is unique in terms of it’s function.

# How To Determine A Resistor Size

Resistors are commonly used in electronics projects and it’s important to know which size to use. To find the resistor value, you need to know the voltage and the amps for your LED and battery.

A standard LED generally needs a voltage of around 2V and a current of 20mA or .02A to operate correctly. Next, you need to find out what voltage your battery is. In this example, we will be using a 9V battery. In order to determine the resistor size, we need to use a formula known as Ohm’s law as shown below.

Ohm’s Law – Resistance (R) = Voltage (V) / Current (I)

Resistance is measured in Ohms (Ω)
Voltage is measured in volts (V)
Current is measured in amps (A)

Using Ohm’s law, you need to subtract the LED voltage from the battery voltage. This will give you a voltage of 7 which needs to be divided by .02 amps from the LED. This formula shows that you will need a 350 Ω resistor.

As a note, standard resistors don’t come in 350 Ω but are available in 330 Ω which will work fine.