CIRSIM : Version 3.0

CIRSIM is the Windows version of the simulation program. It can be used to calculate the steady state performance of circuits containing up to 100 nodes with any combination of resistors, capacitors, inductors, centre-tapped transformers, mutual inductors, transistors (bipolar and FET), op-amps and thermionic valves. The output displays the gain (in dB), phase shift and the input and output impedances of the network at any given frequency. Component and frequency values may be input using the symbols p,n,u,m,k,M,G and T as multipliers. The circuit values are stored in a text file on disk - values may be modified at any time using the program editor, extra components and nodes can be added or deleted and input and output nodes redefined. A listing of the component and node values for each circuit may be printed out. A demonstration version of the program handling a maximum of 6 nodes can be downloaded from this site (see below).

Comprehensive graph plotting facilities are also included, with the facility to superimpose amplitude / frequency response plots. Fiftytwo predefined frequency scales extending from 0.03Hz to 3GHz over a range of 1, 2, 3, 5 or 6 decades are provided together with the facility for a user defined frequency scale covering any range. The amplitude scales may be set as required. Typical results in the screenshot below show the amplitude response of a five pole low pass filter :-


And the following plot shows the corresponding squarewave response which exhibits ringing at around the filter cut off frequency :-



CIRSIM can be used to calculate the response of any linear analogue (analog) circuit, such as audio, video, i.f and r.f. amplifiers, active and passive filters, matching networks, etc. It can be used to evaluate the effectiveness of decoupling components and the stability criteria of oscillators. Detailed documentation is included together with many circuit examples, including a transmission line, active and passive filters, various feedback amplifiers, TV IF amplifier, a cascode circuit, a gyrator, a mutually coupled tuned circuit, Quad 303 audio amplifier, Williamson valve power amplifier, a Wien bridge oscillator, a quartz crystal equivalent circuit, Baxandall audio tone control, a loudspeaker crossover network and a multiband graphic equalizer.

Minimum hardware requirements for this latest version of the program are a 386 compatible PC (with coprocessor) and running Windows 9x/Me/NT/XP/Vista with SVGA graphics. Comprehensive testing has been carried out on a range of IBM compatible PCs and a range of popular printers. Comparison of the results obtained using SPICE to analyse some of the circuits shows exact agreement with CIRSIM.

ACNET is the DOS version of the simulation program. It performs in the same way as CIRSIM but is slower in operation and is limited to a maximum of 50 nodes. It will function on any IBM 286 (or above) compatible PC. The graphical output supports Epson (9 and 24 pin), IBM and HP DeskJet printers. Both programs are EDA - Electronic Design Automation - products.


  •   Click here   to view more examples of the simulator output.

  •   Click here   to see CIRSIM REVIEW published in EPE magazine Jan 2001.

  •   Click here   to download demonstration program for Windows and DOS.

  •   Click here   to purchase the full registered version of CIRSIM.


Peter M. Montgomery, Downings, Bells Hill, Stoke Poges, SLOUGH  SL2 4EG (UK)

Telephone : 44(0)1753643384                    

For more details see program documentation or contact the author.


CIRSIM  and  ACNET  :  Copyright    1991- 2010   P.M. Montgomery

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        CIRSIM   :   09/04/2010