Electronic Circuits – Basics

An electric circuit is by definition is an arrangement of electrical components connected so that there is some form of current flow.

I am assuming you are aware of basics of electronics, so I will keep the discussion about those short and focused. The intention of this post is to laydown the foundation which will help us to understand the device landscape and later when we use these concepts in our IoT discussion, then we already have this reference.

In electronic circuits, typically there is a current or voltage source and number of components connected with wire or circuit trace or other conductive means.

All circuits can be analyzed as series or parallel circuits or a combination of both.

Series Circuit

• Series circuit consists of a source of electrical energy like a battery or a solar cell (voltage/current source), a load which does work of the circuit, like a light-bulb or motor, some components or other devices and off course some conductors to connect everything together.
• For a series circuit, everything is connected in series. In a series circuit, all the current flows through every device. A break anywhere in the circuit interrupts the flow of current.

Parallel Circuit

• In parallel circuit, there are multiple paths for current to flow. Multiple components are connected in ladder fashion.
• Current can flow through components without first having to flow through another component.

Complex Circuits

• Many circuits are combination of series and parallel circuits .
• Complex circuits have many paths for the current to flow.

AC/DC Circuits

These are the two popular types of electronic circuits.

DC stands for “Direct Current”. It means that the current if flowing in one direction only. They battery in your car or flash-light generates DC current.

AC current flows in two directions. AC current is generated by generators or inverters. Normally, our house current is of the AC variety.

Current, Voltage, Resistance and Power

To get a feel for the properties of electricity and its behavior in a circuit, we need to to understand in a general sense what the quantities of current, voltage, resistance and power represent.

Ohm’s law

Ohm’s law is a simple equation that relates current, voltage and resistance in terms of one another.

We can use Ohm’s law to solve for one in terms of any of the others. So, knowing any two of the three components, we can solve for the other.

Power Law

• The mathematical relationship between power, current and voltage is known as power law.
• The unit of measure for power is the watt.
• Combining Ohm’s law with the Power law allows us to solve for power in terms current and resistance.

• Here we see a chart relating current, voltage, resistance and power.
• In the upper right quadrant, we see the equations for voltage in terms of current, resistance and power.
• In the lower right quadrant, we see resistance defined in terms of current, voltage and power.
• In the upper left quadrant, we see current defined in terms of voltage, resistance and power.
• And finally, in lower left quadrant, we see power defined in terms of current, voltage and resistance.

Breadboard

• A breadboard enables you to prototype circuits quickly, without having to solder the connections.
• Breadboard is separated down in the middle with a channel. This is typically where an integrated circuit would straddle so that all its pins land on isolated columns.
• The highlighted pins shows the areas of common electrical connections
• The contacts are arranged in rows and columns.
• Each columns, 1 to 30 for this breadboard, has contacts in rows A through E common and contacts in rows F through J common.
• Any device inserted into the same column in rows A, B, C, D or E will be connected, and any device inserted into rows F, G, H, I or J will be connected if on the same column. The rows are not connected.
• Along the top and along the bottom, we have two buses. They are marked blue (minus) and red(plus), and are common through whole bus.
• Anything inserted into the red (plus) bus will be connected, and anything inserted into blue(minus) bus will be connected. These buses are handy to use as power supply rails or input/out signal rails.
• Generally they provide a way to connect a common voltage. They are usually in pairs for +5 volts and ground. These strips are referred to as rails and they enable you to connect power to many components or points in the board .

Summary

In this post, I mentioned basic of electronic circuits and a little bit of theory and few important laws. These concepts are needed when you start designing circuits. We also saw the purpose of Breadboard and using it will help you to quickly prototype different kind of circuits. However, I did not covered “Arduino”, a popular hardware platform, which is used very frequently in prototyping digital solutions and also different kind of electronic components which are needed when designing electronic circuits.The reason was to keep this post focused only to very basics. However moving forward with this blog series, I will try to cover those items in separate posts. Also, I will encourage you to have a look on the official website of Arduino (link below) for more information. Till next time, Happy Coding.

References

• http://woodovoodo.weebly.com/series-circuits.html
• https://www.dlsweb.rmit.edu.au/Toolbox/electrotech/toolbox1204/resources/01principles/05circuits/02parallel.htm
• https://www.arduino.cc/