EFA:001 – Getting Started & Ohm’s Law

What Is in Your Kit?

You have a little box of goodies for the course. Here is a list of the important things that you should have.

Basic stuff

  • Arduino Uno
  • USB cable
  • Breadboard
  • 9V power supply
  • DC power adapter (2.1mm to screw terminal)
  • Some jumper wires
  • Alligator clip cables

General components

  • LEDs
  • LDR (light sensor)
  • Momentary push buttons
  • Resistors (different values)
  • Capacitors (different values)
  • Small signal diodes 1N4148
  • Schottky diodes 1N5819
  • Bipolar junction transistors PN2222
  • Darlington transistor TIP120
  • Diffused Neopixel RGB LEDs


  • 7805 – 5V Voltage Regulator
  • 555 – Timer Chip
  • L293D – Dual H-Bridge Motor Driver
  • 40106 – Schmitt Trigger Inverter
  • 4017 – Decade Counter
  • 4093 – Quad 2-Input NAND Schmitt Trigger

Amplifier Kit (a set of parts for soldering together an audio amplifier)

  • LM386 Amplifier
  • 8-pin IC Socket
  • Small 8Ω speaker
  • 220 uF capacitor
  • 10 uF capacitor
  • 0.1uF capacitor
  • 10kΩ potentiometer
  • 10Ω Resistor

What Is Electricity?



  • Symbol: V (also U in Europe)
  • Unit: Volt (V)

Voltage is the difference in electric potential energy between two points.

In our water analogy, voltage is like the amout of pressure that has the potential to push the water through a water pipe.


  • Symbol: I
  • Unit: Ampere/Amp (A)

Current is the flow of electric charge.

In our water analogy, current would be the water current or water flow. The amount of water that flows in a water pipe.


  • Symbol: R
  • Unit: Ohm (Ω)

Resistance is the measure of a material’s ability to oppose the flow of electricity.

In our water analogy, resistance is like a narrowing or clog in the pipe that makes it harder for the water to flow through.

Ohm’s Law


Important Note: Conventional Flow and Electron Flow

Due to the fact that electricity was discovered before we understood how atoms work, it was first believed that electrical current is something that flows from the positive side to the negative side in a circuit. In reality, electricity is the movement of electrons from one atom to another and it actually happens the other way: from negative to positive.

This has led to two different ways to talk about which way electricity flows. The conventional flow and the electron flow. Most symbols on schematics make more sense, if we talk about electricity according to the conventional flow, also, electrical engineers and text books still mainly use that system.

We are also going to use the conventional flow, since it is a little bit more intuitive to think of it that way based on the water analogy: the current flows from the positive to the negative. The math still works the same no matter which you use. Additionally, we are not going to be working with anything where it would actually be important to understand the actual physics of electrons flowing.

Getting Started

We will go through some common components and tools: