Editing SPICE (section)

== Introduction ==
Unlike board-level designs composed of discrete parts, it is not practical to [[breadboard]] integrated circuits before manufacture. Further, the high costs of [[Photomask|photolithographic masks]] and other manufacturing prerequisites make it essential to design the circuit to be as close to perfect as possible before the integrated circuit is first built.

Simulating the circuit with SPICE is the industry-standard way to verify circuit operation at the transistor level before committing to manufacturing an integrated circuit. The SPICE simulators help to predict the behavior of the IC under different operating conditions, such as different voltage and current levels, temperature variations, and noise.<ref>BTV [https://besttechviews.com/spice-simulators-reviews-metrics/ SPICE Simulators.] Retrieved January 2, 2023</ref>

Board-level circuit designs can often be breadboarded for testing. Even with a breadboard, some circuit properties may not be accurate compared to the final printed wiring board, such as [[Parasitic element (electrical networks)|parasitic resistances and capacitances]], whose effects can often be estimated more accurately using simulation. Also, designers may want more information about the circuit than is available from a single mock-up. For instance, circuit performance is affected by component manufacturing tolerances.  In these cases it is common to use SPICE to perform [[Monte Carlo method|Monte Carlo]] simulations of the effect of component variations on performance, a task which is impractical using calculations by hand for a circuit of any appreciable complexity.

Circuit simulation programs, of which SPICE and derivatives are the most prominent, take a text [[netlist]] describing the circuit elements ([[transistors]], [[resistors]], [[capacitors]], etc.) and their connections, and translate<ref>{{cite journal |first=Colin |last=Warwick |url=http://www.nutwooduk.co.uk/pdf/Issue82.PDF#page=27 |journal = EMC Journal |issue = 82 |pages = 27–29 |date = May 2009 |title = Everything you always wanted to know about SPICE* (*But were afraid to ask) |format = PDF}}</ref> this description into equations to be solved.  The general equations produced are [[nonlinear system|nonlinear]] [[differential algebraic equation]]s which are solved using [[Explicit and implicit methods|implicit integration methods]], [[Newton's method]] and [[sparse matrix]] techniques.