Source: https://mokxi.com/parts/funcgen Updated: 2026-11-10 Part # Function generator The bench box: four shapes, knobs on the face, and a real 50 ohm output that a load pulls down. See every part - 2 pins - 5 settings - In 6 projects - In 5 lessons Drawn live by the editor's own code, at the size you see it. At a glance ## The Function generator in brief What it is, and every setting the properties panel gives it. A bench function generator makes a repeating waveform at a frequency and level you dial in; it is the source for testing filters, amplifiers and anything a sketch must measure. Mokxi’s has two terminals, OUT and GND, and four shapes: sine, square, triangle, and the sawtooth that nothing else in the catalog produces. Frequency defaults to 1000 Hz and amplitude to 2.5 volts peak around a 2.5 volt offset, so the stock setting swings 0 to 5 volts and suits an Uno analog pin as it is; for an ESP32, lower the amplitude and offset to stay inside 0 to 3.3 volts, and always tie the generator’s GND to the board’s. The square wave has a duty property. Unlike the ideal signal generator part, this one drives through a real 50 ohm resistance in the circuit solver, so into 50 ohms you measure half the amplitude you set and into 1k about 95 percent, as on a real bench box. The solver lands exactly on every square edge. Distortion, rise time, noise, sweep, modulation and any output current limit are not modeled. Family Timers and analog Pins 2 wave sine (or square, triangle, sawtooth) sine, square, triangle or sawtooth. frequency 1000 in hertz, 1000 by default. amplitude 2.5 the peak swing either side of offset, 2.5 by default. offset 2.5 2.5 by default, so the stock settings give a 0 V to 5 V swing. duty 50 the square wave's duty cycle, 50 by default. A circuit built around it, running and explained: the Function generator simulator. Pins ## 2 pins Named as the editor names them, so a wire lands where you expect it. Pin Role What it does OUT Input or output The waveform, behind 50 ohms. GND Input The reference the waveform is measured against. How to use it ## How to use a bench function generator Wire OUT to the node you want to drive and GND to the circuit’s ground, then pick the shape, frequency and amplitude with the buttons on its face, which step 1, 2, 5 per decade the way a real dial is marked. Offset and duty are in the properties panel. An offset of 0 swings the wave either side of ground, as here; the default 2.5 V gives 0 to 5 V. The circuit here sends a 100 Hz, 2 V sine into a 16 k and 0.1 uF low pass with a scope on both ends. Sweep it by hand: at 20 Hz the two traces nearly overlap, at 100 Hz the output is 0.707 of the input and 45 degrees behind, and by 2 kHz it has all but gone. The generator’s 50 ohms is nothing against 16 k. Part pin Board pin OUT The 16 k resistor, and scope CH1 GND The ground rail Scope CH2 The filtered node across the capacitor Into an Arduino analog pin, keep the wave inside 0 to 5 V on an Uno and 0 to 3.3 V on an ESP32, and join the generator’s GND to the board’s. Click to open it in the editor This is the simulator itself, running here. Click anything to open it in the editor. Open this project in the editor Read the full tutorial How it is modeled ## What is true about the Function generator, here In its help article’s own words: what the simulation gets right, and where it stops. ### Modeled The waveform goes into the analog solver rather than being stepped by the part, so the solver puts a breakpoint on every square-wave edge and every sawtooth fly-back and lands exactly on it instead of integrating through it. The 50 ohms is a real element in the matrix, not a correction applied afterwards: into 50 ohms you measure half the amplitude you asked for, into 1 k about 95% of it, into a megohm all of it. ### Not modeled No distortion, no amplitude or frequency drift, no sweep mode. A sweep here is pressing the frequency button, which is a step rather than a glide. No modulation and no burst. The waveform is mathematically exact: a square wave's edges are vertical with no rise time, a sine has no harmonics, and there is no noise floor, no jitter and no DC offset error. The 50 ohms is a pure resistance with no reactance and no frequency dependence. There is no output protection or current limit (the generator will drive a short circuit forever) and no upper frequency limit other than what the solver's own step can follow, so asking for a megahertz gives a megahertz rather than the rolled-off, distorted thing a real box would produce. From Function generator, in full. Projects ## See the Function generator in a project 6 built-in projects use it. Each opens in the editor, already wired. Lessons ## Where it turns up in a lesson 5 lessons place it in their own circuits. ### Learn articles 5 lessons - LM358 Op-Amp Simulator: Pinout, Gain and Comparator - RC Filter Simulator With a Bode Plot - Op-Amp Amplifier Simulator, Gain of 10 - RLC Circuit Simulator: Series Resonance and Q, Live - Active Low Pass Filter With an Op-Amp, Simulated Boards ## The boards it is shown on This board has a built-in project with the Function generator in it. - Arduino Uno R3 More parts ## The rest of the bench Every one of these is drawn and simulated the same way. Full-size breadboard A real 0.1 inch grid with the rails and the center channel, 63 columns wide. Jumper wires Drag from any pin or hole to any other. Corners snap, and you can drag them. Power A supply rail at the voltage you choose. Ground The other end of every circuit. LED Lights when current flows. Five colors, and the brightness is what your eye would see. Filament lamp A tungsten bulb in a holder: an inrush when it is switched on cold, tens of milliseconds to warm up, and dim on half its voltage. Resistor Any value you like, with the color bands drawn to match. ESP32-C3-DevKitM-1 A RISC-V board that runs your firmware at 160 MHz on the real memory map. Pushbutton A 12 mm tactile switch. Hold it while the simulation runs. Raspberry Pi Pico The RP2040 board on our own Cortex-M0+ core. Pick a program and press Run. Raspberry Pi Pico W Raspberry Pi Pico W (RP2040). The same board and the same pinout as a Pico, with the CYW43439 on it. The WiFi is simulated (no radio; real internet through the Cloud panel’s switch), and the on-board LED, which hangs off that chip rather than off GP25, is driven through the same path. Everything else is the Pico. Raspberry Pi 4 Model B Raspberry Pi 4 Model B: the 40-pin header, driven by main.py with RPi.GPIO or gpiozero. See every part ## Wire up the Function generator Open the editor and push it into the breadboard. It is free, and it runs on your own machine. Start building free Open the editor