SPICE is a general-purpose circuit simulation program for nonlinear dc, nonlinear transient, and linear ac analyses. Circuits may contain resistors, capacitors, inductors, mutual inductors, independent voltage and current sources, four types of dependent sources, lossless and lossy transmission lines (two separate implementations), switches, uniform distributed RC lines, and the five most common semiconductor devices: diodes, BJTs, JFETs, MESFETs, and MOSFETs. SPICE originates from the EECS Department of the University of California at Berkeley.

This page provides manual pages, a user guide, and example runs for the Spice3f version of the program.

More details are given the link:

http://bwrcs.eecs.berkeley.edu/Classes/IcBook/SPICE/

Many years ago, when I was still a student, I used to use PSPICE. If I remember it correctly, at that time, PSPICE student version was free. I don't know whether it is still free or not.

http://bwrcs.eecs.berkeley.edu/Classes/IcBook/SPICE/

Student version 9.1 still free :)

SPICE is a general-purpose circuit simulation program for nonlinear dc, nonlinear transient, and linear ac analyses. Circuits may contain resistors, capacitors, inductors, mutual inductors, independent voltage and current sources, four types of dependent sources, lossless and lossy transmission lines (two separate implementations), switches, uniform distributed RC lines, and the five most common semiconductor devices: diodes, BJTs, JFETs, MESFETs, and MOSFETs. SPICE originates from the EECS Department of the University of California at Berkeley.

This page provides manual pages, a user guide, and example runs for the Spice3f version of the program.

More details are given the link:

http://bwrcs.eecs.berkeley.edu/Classes/IcBook/SPICE/

Dear @Sundar, there is the list of many available free circuit simulators for circuit design!

Electronic circuit simulators distributed under a free software license are available from several sources and for several computing platforms.

http://en.wikipedia.org/wiki/List_of_free_electronics_circuit_simulators

http://en.wikipedia.org/wiki/SPICE

I recommend freeware SPICE software named as "NG-SPICE". following is the link.

http://ngspice.sourceforge.net/

Commercial ones which are popular:  HSPICE, Cadence Virtuoso

I'm using LTSpice a lot, it's available for free through Linear Technology.

The keyboard mapping is a bit weird, but it calculates very fast, and is very good in convergence.

On the long term it really pays off to write .cir description by hand. However, there is a learning curve and if someone needs to simulate only once circuit, graphical interface may be beneficial. Otherwise I agree with previously written comment - learn to use spice3f in general (open source/free software). May I also recommend to consider SpiceOPUS, which has a nice graphing interface. It is commercial software with freeware version -- mostly limiting the number of nodes and optimization capabilities. 

http://www.spiceopus.si/

I have been using, Quite Universal Circuit Simulator (QUCS) to teach Circuit Theory, for several semesters now. It is not a SPICE simulator, but can import spice netlists with a small effort. It is freely available, practical and learning is quite easy. Although it lacks several features yet, it's ability to simulate equation based devices, distributed components and direct connection to Octave (MATLAB clone) is very nice.

http://qucs.sourceforge.net/

One can try using TINA-Ti by Texas Instruments. It is a free ware. Earlier I used to design using CIRCUIT MAKER. It was a free ware. I don't know if it is still available.

These are the three that I use.

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LTspice from Linear is free:

http://www.linear.com/designtools/software/

... and has a lot of support for specific Linear parts (which work), as opposed to genetic models.

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Beige Bag Softwere's B2.Spice A/D Circuit Simulation Software is commercial but "affordable" at $595 and there is a student edition subscription at $10 per month.

http://www.beigebag.com/

.. I use the V5 older version.

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Mentor Graphics have HyperLynx Analog in their PADS suite.

http://www.mentor.com/pcb/hyperlynx/analog/

And also HyperLynx for signal integrity of digital stuff (clocks, DDRx RAM, multi Gb serdes, etc.).

http://www.pads.com/analysis/signal-integrity

The PADS VX suite is full-on commercial design software, and is suitably expensive. However there is an educational subscription for "not for profit" use which is more affordable.

If one is teaching student lab, then the free stuff is often good enough. If your group is designing acquisition boards for the LHC at CERN etc., or space experimental stuff then go straight to the PADS VX or Cadence equivalent.

http://www.cadence.com/products/pcb/spice/pages/default.aspx

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There are 2 types of commercially available SPICE simulators: Traditional or accurate SPICE (for small or accurate circuits) and fast SPICE (for full chip or big circuits). There are 3 main vendors for SPICE simulators (and for almost everything else in EDA): Cadence, Mentor and Synopsys.

Cadence Spectre is THE dominant accurate SPICE simulator used across industry. Its not exactly a SPICE simulator but rather a SPICE "like" simulator (SPICE commands don't run on Spectre as it is) but for all practical purposes you may count it as one. Its GUI is very user friendly. Its PSS simulation is THE standard of the phase noise related simulations. Mentor's ELDO is also a very good accurate SPICE simulator if you want pure SPICE simulator. Its user manual is very well written. Its .extract command is very rich and its waveform viewer EZwave is very user friendly and intuitive. Synopsis HSPICE is a poor alternate as compared to Spectre and ELDO. Its user manual is pathetic, waveview is frustrating and options for recursive simulations (sweep commands) are very limited. I recommend it only if you don't have to do pure analog simulation but only some custom circuit simulations like standard cells or IO.

For fast SPICE Synopsis nanosim is good and is widely used in memories for system level simulations. Cadence XPS is also good.

Hope it helps.

Saurabh.

The Quite Universal Circuit Simulator, Qucs , is a free and Open source software, which is an integrated environment for circuit simulation with a very good interface.

It is an interesting free product used by many universities. You can download and test from link below. It runs on many operating systems.

 http://qucs.sourceforge.net/index.html

You can use PSpice !