Circuit Layout Simulation Tools Overview

Study Notes

A Circuit Layout Simulation Tool is a software program that emulates the behavior of a real hardware circuit before it is actually built.
It can be used to verify that the hardware design is working correctly and producing the expected output signals for a given set of inputs.
This process is referred to as circuit simulation, where a model of the electronic circuit is created and analyzed using software algorithms.
Circuit simulation is a cost-effective way to verify the functionality and performance of a circuit before actual fabrication, especially for expensive and time-consuming processes like integrated circuits.
Different types of circuit simulators exist, each catering to varying needs across the accuracy-performance/capacity spectrum.

These simulators use functional representations of electronic circuits, typically described using hardware description languages (HDLs).
They offer the highest performance and capacity but at lower levels of accuracy.
They are commonly used for simulating very large circuits.

These simplify the design and product selection process by providing easy-to-use tools and accurate simulations.
They are web-based or downloadable, but not always free to use.
They offer the following benefits:
- Reduced testing time, leading to faster product development.
- Overcoming engineering challenges and simplifying calculations.
- Using industry-leading products to create optimal designs.
- Greater confidence in results and solutions.

These are graphical representations of electrical circuits.
Pictorial circuit diagrams use simple images of components.
Schematic diagrams depict components and interconnections using standardized symbolic representations.
Unlike block diagrams or layout diagrams, circuit diagrams show the actual electrical connections.
Drawings that show the physical arrangement of wires and components are called artwork, layout, physical design, or wiring diagrams.
Circuit diagrams are used for designing, building, and maintaining electrical and electronic equipment.

Circuit diagrams use symbols to represent components.
These symbols have evolved over time, and there are some differences between countries.
Standardization efforts have made symbols more consistent internationally.
Some earlier symbols were meant to represent the physical construction of the device.
For example, the early symbol for a resistor reflected its construction using a long wire wrapped in a way to minimize inductance.
Nowadays, internationally standardized symbols are simplified and often just show the component type with values written inside.
Wire crossover symbols are used to represent wire crossings without showing a connection, while symbols indicating actual connections are used where applicable.
Each symbol has a specific meaning and aids in understanding the circuit's functionality.

Physical relationships between components are important in electrical and electronic drawings.
These drawings are called wiring diagrams and are used for assembly and production of electronic packages.
The correct representation of wire is critical.
Different assemblies use different wire sizes, styles, and types.

Wire is made of copper or aluminum to allow current to flow with little resistance.
It connects two points together without altering the electrical characteristics of the circuit.
Wire can be single strand or multi stranded and is usually covered with insulating materials like nylon, enamel, polyester, rubber, or other materials.
The size of the wire (cross-sectional area) can vary.
Insulation can be of different colours to help technicians identify the wire and its function.
This colour, type and size information is included in the wiring diagram so technicians can trace circuits and make repairs.
The wire gauge is a measurement of the size of the wire.
Wire gauges are based on the American Wire Gauge (AWG) Standards, with smaller numbers indicating larger wire sizes.
Larger wire sizes can handle higher current.

Wire sizes range from very fine (like hair) to relatively thick (similar to a small finger).
Each wire size has different electrical characteristics, such as the amount of resistance and the maximum current it can carry.
Stranded wire is formed from multiple strands of smaller wire, giving it added flexibility.
Stranded wire can only carry about 60% of the current of solid wire with a similar cross-sectional area.
To find the equivalent solid wire size, multiply the number of strands by the cross-sectional area of each individual strand.
Stranded wire is often described by the number of strands and the AWG number of each individual strand (e.g. 8/34).

Many different materials are used to insulate wires,
Insulation is needed to protect people and prevent wires from touching each other or metal enclosures.
Connecting two conductors creates an electrical connection.
Wire is only designed to connect components, so it should only touch the leads of the components, not other wires.