What is Electronic Circuits?
All the electronic devices we use today are based on complex electronic circuits. Electronic circuits combine components, wires, and electricity to perform certain functions.
Basic Circuit
The basic electronic circuit has a power source, wires connecting components and components. Here is a simple example showing several resistors connected in parallel and in series.
Schematic
Drawings of complex electronic circuits are called schematics. The diagrams show how the different components are connected to each other. Having standard symbols for different components allows different engineers to work on the same project.
Printed Circuit Board
A printed circuit board is used to connect many different electronic components in a working circuit. The “wires” that connect the components are integrated directly into the board. There are even different layers of the board, with each layer having its own set of wires. Small holes called “vias” are drilled through the board to create a layer-to-layer connection. These components are then soldered to the surface of the board to create an electrical connection.
Power and Ground
In a complex printed circuit board, there will usually be at least one layer dedicated to grounding and one layer for power. The base layer is called the ground. The background plane serves as the current return path for many components. Most active components have at least one pin that must connect to ground.
A complex circuit also usually has at least one DC power source. On some very complex circuit boards, there can be multiple supplies. A typical power supply will be +3.3V, +2.5V or +1.8V depending on the technology used. In general, a complete layer of the circuit board is dedicated to the mains voltage. This power supply is used to power the active components.
Passive Components
Passive components in a circuit are those that do not require any external power source. They are in the current path of the circuit and do not need to be connected to a power source. Some examples of passive components include resistors, capacitors, inductors, and connectors.
Active Components
The active components of the circuit require an external power source. They connect to a power source and can transfer power to a circuit, for example by amplifying a signal. Examples of active components include diodes, transistors, and integrated circuits like your computer’s processor.
Interesting Facts about Electronic Circuits
The ground is often abbreviated as GND or has a symbol that looks like an arrow or an upside down triangle.
The term “printed circuit board” is often abbreviated as PCB.
An analog circuit is a circuit whose current or voltage varies continuously with time.
A digital circuit is a circuit in which electrical signals have definite values representing zeros and zeros.
There can be extremely complex circuits inside a computer chip. High-end computer processors have circuits made up of billions of transistors.