A lot of people desire so much to know the concepts of electronic circuit design from scratch. Well, designing simple lighting systems with bunch of light emitting diodes and resistors may not really pose problems, but becoming good at designing complex electronic systems is not a child’s play. Nevertheless, there is no limit to what anyone can achieve if they are bent on doing so.
Some people search for circuits online, get the circuit diagram, construct it, and after which they see themselves as they have designed electronic circuit. Unfortunately, that is not electronic circuit design.
You can see yourself as having designed a circuit if you think of an electronic device you want to bring to life, then work your way around it from scratch and come up with a satisfying result.
Teaching you how to do this is what I will cover in this tutorial, I will add some videos as well to make the knowledge sink deeper and better.
Basic rules of electronic circuit design
Any well-built electronic device has a manual. This manual contains instructions on how to effectively use the device. If you follow the manual to the last detail, rest assured you will make the best out of the device. Same hunch is applicable to electronic circuit design, there are basic rules of electronic circuit design which every beginner in electronic circuit design must know:
- Mastering the various electronic components and how they behave in a circuit: Electronic circuit design can be likened to the game of soccer or any game that has a team and a coach, the coach is you the circuit designer, while the players are the various electronic components. For the coach to expect winning the game, he/she must place the players in their rightful wings, same thing is applicable to electronic circuit design, for the circuit designer to realize the desired design result, he/she must place the electronic components in their rightful positions in the circuit. Knowing how to do that is what I will teach you in this tutorial and in other circuit design tutorials.
Therefore, as an electronic circuit designer, you must know to a reasonable extent how the various electronic components behave and how to use them in a circuit.
You must not know all the electronic components, however, knowing a handful of them is necessary. Components like; resistor, capacitor, inductor, diode, switches, battery, transistor, thyristor, triac, diac, 555 timer IC, regulator, transformer, light emitting diode LED, etc.
2. More current will tend to flow through the least resistive in a circuit: Let’s say you already know what current and voltage is all about in electronics, if you have not, then read a comprehensive tutorial on that here. Every circuit has resistance, resistance defines how current is distributed in a circuit. The component that categorically contributes resistance in a circuit as its function is called a resistor. figure 2 above shows bunch of colour-coded resistors.
resistors come in different sizes and shapes, above all, they come in different values, so, if we have a resistor of 10k and 100k both connected in a circuit in parallel, we will observe that more current will flow in the part with 10k resistor. see the circuit diagram and simulation below:
when you look at the simulation closely, you will see that more current is flowing through the path that has the 10k resistor than the path that has 100k resistor. with this illustration, you will understand that electrical resistance can be used to determine how current flows in a circuit. And that is what electronics is all about. Electronics is simply the use of electronic components to manipulate the flow of current to achieve a desired aim in a circuit.
Current will flow from a region of higher electrical potential or voltage to a region of lower potential or voltage: Look at the circuit below
the current coming out of the power source in the circuit will never flow from point B to point A but the other way round as indicated by the arrows. Just as we know that water does not flow uphill. This is because the energy (voltage) of the current at point A is bigger than the energy (Voltage) at point B. to understand this better watch this video tutorial.
4. Current flows in circuit to return to ground: Ground is the lowest potential point in a circuit, it can be seen as the negative terminal of a battery or power supply. It is the part of the circuit that is the lowest level in electronic energy or voltage upon which the voltage or electrical potential of other points in the circuit are measured. The ground is the reference point for measuring test point voltages in a circuit. See circuit diagram below:
The part circled in red is the ground, its voltage is zero as shown in the image.
Once you’ve acquainted yourself with this rules and concepts of electronic circuit design and you have learnt the behavior of some electronic components, the next line of action will be to start your design, to do that you will need the following electronic components:
- Breadboard: I have made a very comprehensive tutorial on how to use a breadboard, click here to read it.
- Jumper wires
- Light emitting diode
The circuit we will design here is the simplest and commonest circuit a beginner starts with, it is a circuit that turns ON and OFF an LED, it is like writing “Hello world!” in computer programming See the circuit diagram below:
Circuit analysis of the design
The battery supplies the electrical energy required to energize the circuit. The switch opens or closes the path of current flow in a circuit, the switch creates an open loop or closed loop in the circuit, I will talk about this in the next tutorial. The resistor limits the rate of current flow in the circuit to prevent excess current and voltage from damaging the light emitting diode. It should be noted that light emitting diodes have specific amount of current and voltage they should be exposed to, else they will get damaged, this voltage is typically around 2-3 volts. The LED emits light when the switch is turned on.
Electronic circuit simulation with Proteus
If you can’t lay hands on electronic components at the moment, don’t worry, you can still experience electronic circuit design using a circuit simulator like Proteus. To use this simulator, you need to install it on your PC. Once you are ready to carry out your simulation, watch the video below:
I simulated how to turn ON and turn OFF an LED in the tutorial, it is a very simple tutorial.
Proteus is very easy to use. Once you have carried out your simulation, you can try this second simulation, you can watch the videos below or click this link to read and watch the tutorial
As a beginner in electronic circuit design, you should start with simple designs and walk your way up. To be good at this requires that you be creative, being creative entails thinking out problems, then use your knowledge of how the electronic components behave to tackle them. Once you can handle designing simple circuits, you should proceed to more difficult ones and also learn circuit analysis. I will be making tutorials on circuit analysis in the future. As you practice circuit design, also try repairing some faulty devices, it helps to build the confidence, I have a mantra that says: “to be good at design, go and learn repairs”.
Learn how to use some test gears like Multimeter, Oscilloscope if you can afford one, LCR meter, etc. above all, practice is the only action that can make you a good circuit designer, cultivate the habit of practicing and trying out every idea. Once you have gained reasonable strength in non-programmable electronics, it is now time to delve into the use of Microcontrollers, like Arduino, or Raspberry pi. I have a list of Arduino tutorials and Arduino projects readily available you can click here for Arduino tutorials and here for Arduino projects.
I believe this tutorial gives you the necessary beginners’ guide to learning how to design electronic circuit from scratch. If you have any questions let me know in the comment section.