 # Technology Time Notes

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# Conceptualize Digital Circuit Design

This tutorial will teach you all about designing digital circuits. If you’re looking for a guide that provides a complete overview of this topic, then you’ve come to the right place! The first section will introduce you to the concept of digital circuits and explain how they work. Next, we’ll discuss the components that comprise them: gates and switches. Then we’ll walk through each step of the modeling process for digital circuits before moving on to show how these designs are made into real-life objects using CAD software such as Cadence or Mentor Graphics.

## Digital Circuit Design

A digital circuit is a circuit that uses discrete values to represent information. These discrete values are called bits, which are 0 or 1. An example of a digital circuit would be an alarm system that sounds when the door opens if there’s no movement detected by the sensors, then it doesn’t go off; if there is movement, then it does go off. In this chapter we’ll talk about how to conceptualize and design your own digital circuits using these tools:

• Schematics editor (to draw schematics)
• Simulation software (to test your designs before building them)

## The Components of a Digital Circuit Design

A digital circuit consists of gates and wires. The building blocks of design digital circuits are called gates, and they take inputs from other gates and produce outputs based on those inputs. The only types of gates you will use in this course are AND, OR, and NOT (inverter). The wires are simply connections between the various components of your circuit; they allow signals to flow through your circuit so that information can be processed by each component as needed.

## The Modeling of a Digital Circuit Design

Before you can design a digital circuit, you need to be able to model the circuit. This involves translating Boolean algebra expressions into circuit diagrams and vice versa.

• Boolean Algebra: Boolean algebra is a system of equations used to represent digital circuits as mathematical statements that can be manipulated using basic arithmetic operations such as addition, subtraction, and multiplication. The most common example of Boolean algebra is the AND gate which has two inputs (A and B) and one output (O). In this case A + B = O or A x B = O where x represents the operation performed on A by B.
• Circuit Diagrams: Circuit diagrams are used in electronics engineering as a means for representing electrical components such as resistors and capacitors using graphical symbols instead of text descriptions or schematics which are more technical but less intuitive for non-specialists such as designers who don’t understand how transistors work but only want them so they know what kind they need when buying parts online from Sparkfun Electronics where I worked during college summers while studying Computer Engineering at University Of Massachusetts Amherst.

## The Design Process for Digital Circuit Design

The design process for digital circuits is a bit different from that of analog circuits. The design process for digital circuits is more systematic than that of analog circuits. The design process for digital circuits is also more mathematical than that of analog circuits. In the design of both digital and analog circuits, we first have to know the specifications of the device that will be using the circuit. The specifications include things like voltage levels, current levels, timing requirements, etc. We also need to determine what type of logic is going to be used in our circuit (i.e., CMOS or TTL), as well as how many inputs and outputs are needed for it.