#ICIRCUIT FREE WINDOWS 10 CODE#
The license originally included distribution restrictions for countries not considered friendly to the US, but the source code is currently covered by the BSD license. SPICE source code was from the beginning distributed by UC Berkeley for a nominal charge (to cover the cost of magnetic tape). Its ubiquity became such that "to SPICE a circuit" remains synonymous with circuit simulation.
#ICIRCUIT FREE WINDOWS 10 SOFTWARE#
Īs an early public domain software program with source code available, SPICE was widely distributed and used. It is written in C, uses the same netlist syntax, and added X Window System plotting. SPICE3 was developed by Thomas Quarles (with A. The last FORTRAN version of SPICE is 2G.6 in 1983. SPICE2, also coded in FORTRAN, is a much-improved program with more circuit elements, variable timestep transient analysis using either the trapezoidal (second order Adams-Moulton method) or the Gear integration method (also known as BDF), equation formulation via modified nodal analysis (avoiding the limitations of nodal analysis), and an innovative FORTRAN-based memory allocation system developed by another graduate student, Ellis Cohen. The real popularity of SPICE started with SPICE2 in 1975. SPICE1 has relatively few circuit elements available and uses a fixed-timestep transient analysis. SPICE1 is coded in FORTRAN and to construct the circuit equations uses nodal analysis, which has limitations in representing inductors, floating voltage sources and the various forms of controlled sources. SPICE1 was first presented at a conference in 1973. Pederson insisted that CANCER, a proprietary program, be rewritten enough that restrictions could be removed and the program could be put in the public domain. CANCER is an acronym for "Computer Analysis of Nonlinear Circuits, Excluding Radiation", a hint to Berkeley's liberalism in the 1960s: at these times many circuit simulators were developed under contracts with the United States Department of Defense that required the capability to evaluate the radiation hardness of a circuit. SPICE1 is largely a derivative of the CANCER program, SPICE was developed at the Electronics Research Laboratory of the University of California, Berkeley by Laurence Nagel with direction from his research advisor, Prof. The general equations produced are nonlinear differential algebraic equations which are solved using implicit integration methods, Newton's method and sparse matrix techniques. In these cases it is common to use SPICE to perform 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.Ĭircuit 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 this description into equations to be solved.
For instance, circuit performance is affected by component manufacturing tolerances. Also, designers may want more information about the circuit than is available from a single mock-up. Even with a breadboard, some circuit properties may not be accurate compared to the final printed wiring board, such as parasitic resistances and capacitances, whose effects can often be estimated more accurately using simulation. 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.īoard-level circuit designs can often be breadboarded for testing. Further, the high costs of 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. Unlike board-level designs composed of discrete parts, it is not practical to breadboard integrated circuits before manufacture. 5 SPICE usage beyond electronic simulation.4.3 Input and output: Netlists, schematic capture and plotting.
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