Example Circuits
Here you can download some schematics to test with Qucs. (Qucs schematic files are plain text files!) All users of Qucs are invited to contribute to these examples. If you want to share a schematic or circuit model do not hesitate to do so.
Simulation Examples
| DC simulation | bridge.sch | two-dimensional DC sweep |
| Mirrors_prj.tar.gz | collection of current mirror schematics using mos and bipolar | |
| charac.sch | output characteristics of a bipolar transistor | |
| diff1.sch | large-signal characteristic of a differential amplifier | |
| fgummel.sch | forward gummel characteristic of a bipolar transistor | |
| rgummel.sch | reverse gummel characteristic of a bipolar transistor | |
| preregulator.sch | simple series pre-regulator circuit | |
| AC simulation | swr_meter.sch | circuit of an SWR meter |
| gyrator.sch | a primitive gyrator circuit | |
| resonance.sch | shows voltage overshot of series resonance circuit | |
| stab.sch | simulates stability of feedback circuit | |
| active_bp.sch | a simple bandpass filter with OpAmp | |
| active_lp.sch | active 6th order Chebyshev low-pass filter | |
| bbv.sch | a BJT broadband amplifier circuit | |
| singleOPV.sch | subcircuit of an small, internally compensated MOS OpAmp | |
| gain.sch | simple example for "singleOPV.sch" (needs the circuit above to be run) | |
| notch.sch | a 50Hz notch filter realized with OpAmp gyrator | |
| selective_amp.sch | classic selective RF amplifier | |
| Amp4.zip | audio amplifier provided by John H. Ludwig | |
| MillerAmp_prj.zip | general purpose amplifier provided by John H. Ludwig | |
| bjt_noise.zip | simple flicker noise simulation for a BJT provided by Antonio | |
| 1838MHz_PLL_prj.tar.gz | 1838MHz PLL modelling including noise provided by M.J. Head | |
| groupdelay_ac.sch | group delay of a Butterworth filter using AC simulation | |
| qucs-radiometer-model.tgz | radiometer model provided by Andrea Zonca | |
| Transient simulation | mixer.sch | a double-balanced mixer |
| lf_osci.sch | an oscillator for low-frequencies | |
| rf_osci.sch | a Peltz oscillator | |
| colpitts.sch | a colpitts oscillator with JFET | |
| classic_osci.sch | a classic oscillator design | |
| multiplier.sch | a charge-pumped voltage multiplier | |
| active_mixer.sch | an active, single-balanced mixer | |
| gilbert.sch | a gilbert cell mixer | |
| sym_osci.sch | a symmetrical MOSFET oscillator | |
| schmitt.sch | a schmitt trigger circuit | |
| colpitts_base.sch | a colpitts oscillator in common-base circuit | |
| supply.sch | a conventional power supply | |
| chargepump.sch | a charge-pump circuit doubling the voltage | |
| lc_osc.sch | a symmetrical LC CMOS oscillator | |
| single_balanced.sch | single-balanced CMOS mixer | |
| Puls3b.sch | fast transient pulse generation | |
| sawtooth-1.sch | sawtooth generator using simple thyristor, thanks to Oswald | |
| sawtooth-2.sch | sawtooth generator using opamp integrator, thanks to Oswald | |
| sawtooth-3.sch | sawtooth generator using flip-flop | |
| sawtooth-discreet.sch | sawtooth generator using thyristor, thanks to Oswald | |
| time_resistor.sch | time-dependent variable resistor | |
| vfile_test_tran.tar.gz | test of file-based voltage source | |
| fullwaverectifier_1.sch | full-wave rectifier using a transformer and 2 diodes | |
| fullwaverectifier_2.sch | Gratz bridge rectifier: a full-wave rectifier using 4 diodes | |
| buckconverter.sch | buck converter (step-down DC-DC converter) circuit | |
| boostconverter.sch | boost converter (step-up DC-DC converter) circuit | |
| buckboost.sch | inverting buck/boost converter circuit | |
| S-parameter simulation | elliptic_5th.sch | a 5th order low pass elliptic filter |
| chebyshev1_5th.sch | a 5th order low pass Chebyshev type 1 filter | |
| fhr01fh.sch | small-signal model of a Fujitsu HEMT (including noise analysis) | |
| giacoletto.sch | modified Giacoletto equivalent circuit | |
| fet.sch | small-signal model of a high gain FET (subcircuit) | |
| fet_noise.sch | noise matching of the FET in fet.sch | |
| microstrip.sch | simple examples how to use microstrip components | |
| bpf_10Ghz.sch | a microstrip band pass filter created by Toyoyuki Ishikawa | |
| opamp_gyrator.sch | gyrator with operational amplifier | |
| wilkinson.sch | an ideal Wilkinson divider | |
| 2StageAmplifier_prj.tar.gz | building a two-stage RF amplifier with stabilization, noise and power matching | |
| groupdelay_sp.sch | group delay of a Butterworth filter using S-parameter simulation | |
| SmithChartTest.sch | Smith chart example test with a band pass filter | |
| Digital simulation | DigitalAdder_prj.tar.gz | four-bit adder using one-bit halfadders and fulladders |
| flip_flops_models_tran_prj.zip | collection of flip-flop models usable for digital as well as transient simulation | |
| BCD_prj.tar.gz | four-bit synchronous BCD counter | |
| Harmonic balance | diode_hb.sch | very simple diode setup for demonstration purposes only |
Simulation Models
| Macro and circuit models | LM317_prj.tar.gz | LM317 voltage regulator(s) using different SPICE models |
| 555_examples_prj.tar.gz | famous 555 timer macromodel and examples | |
| IdealBalun.sch | ideal balun model | |
| LPF-Balun2.sch | low-pass filter using ideal balun | |
| LPF-Balun3.sch | another low-pass filter using ideal balun | |
| Device models | curtice1_MESFET_prj.tar.gz | Curtice level 1 MESFET model |
| shot.sch | universal shot noise subcircuit | |
| flicker.sch | flicker noise subcircuit | |
| triode.sch | triode tube model | |
| pentode.sch | pentode tube model | |
| Complete projects | RADAR2010_prj.zip | project on radar circuits (attenuators, duplexers, limiters, phase shifters) and subsystems (T/R modules and reflect arrays) for a tutorial (tested with version 0.0.15) given at the 2010 IEEE Radar Conference, by K. Van Caekenberghe |
| PVcell_Miguel_Pareja.zip | Photovoltaic Cell simulation with QUCS, by Miguel Pareja | |
| High_Voltage_Supply_prj.tar.gz | High voltage power supply, by Richard Crozier | |
| UHF_Amplifier_prj.tar.gz | UHF amplifier with optimization, by Richard Crozier | |
| BSIMTests_prj.zip | BSIM3 and BSIM4 test examples (tested with version 0.0.18), by Mike Brinson |