Ohmira: Circuit Simulator

Ohmira turns electronics into something you can see. Place real components on a grid, wire them together, press Run, and watch voltage colour the wires while moving dots show you where the current goes.

No account. No ads. No network. Nothing to sign up for.

BUILD IT
Drop parts on the grid and drag between terminals to wire them. Parts snap to the grid, wires route themselves around what is in the way, and every action can be undone. Tidy a messy circuit with one tap and it redraws itself as a schematic: the source standing up on the left, the ground at the bottom.

OBSERVE IT
Run the circuit and it stays live. Wires take the colour of their voltage, from grey at 0 V to indigo at the supply. Dots travel along them at the speed of the current. Tap any part to read its voltage, its current and its power, or pin the readings to the canvas and watch them change as you edit.

LEARN IT
Thirty exercises, in three tiers, from Ohm's law to a regulated power supply. Each one gives you a brief and then checks the circuit you actually built, not a multiple-choice question about it. When it fails, it tells you why in words about your circuit: a part missing, a value wrong, a terminal left unwired, a reading that came out too low.

WHAT IS IN THE BOX
• 43 components: sources, batteries, resistors, capacitors, inductors, potentiometers, diodes, LEDs, Zeners, transistors, MOSFETs, an op-amp, bridge rectifiers, regulators, a transformer, relays, lamps, motors, buzzers, thermistors, photoresistors, and probes
• DC analysis, and a transient simulation that draws real waveforms
• A single-channel oscilloscope with a 1-2-5 timebase, mean and peak to peak
• Ten starter circuits, from a single loop to a MOSFET stage
• Labelled zones for grouping parts of a circuit
• Export and import a circuit as a file

MADE FOR PHONES, TABLETS AND FOLDABLES
A workspace on a tablet, with floating panels beside the grid, and a canvas-first layout on a phone: the same editor either way, not a smaller second one. Full TalkBack labels, font scaling, reduce motion, increase contrast, and colour-blind indicators. Colour is never the only thing that carries meaning.

PRIVATE BY DESIGN
Your circuits stay on this device. Ohmira has no account, makes no network call of its own, collects no data, contains no analytics and tracks nothing. There is no backend to leak. To move a circuit to another device, export it to a file and import it there: that is the only way one travels, and you choose the file.

FREE, AND WHAT IS NOT
Ohmira is free, with no time limit and no cap on how many circuits you keep. The free app includes the whole editor, fifteen fundamental parts, the full DC simulation, export and import, the first ten exercises, and six starter circuits.

Ohmira Complete is one purchase, with no subscription, shared with your family. It adds the other 28 components, the remaining 20 exercises, and the oscilloscope.

Ohmira is a teaching simulator, not a SPICE replacement: it is built to make circuits understandable, not to certify a design for manufacture.