When to use: Draw a full schematic — resistors, capacitors, inductors, diodes, LEDs, transistors, op-amps, logic gates, sources and more — by dropping parts on a snap-to-grid canvas, wiring pins together, then running a real DC operating-point analysis. The engine assembles a Modified Nodal Analysis system, references it to ground, and solves it with Gaussian elimination (Newton–Raphson iteration for non-linear diode junctions), reporting node voltages, branch currents and dissipated power for every part.
Every pin sits on an integer grid coordinate. Pins and wire endpoints that share a coordinate are merged into electrical nodes with a union–find pass. The solver stamps each component's conductance (Ohm's law), adds a current unknown for every voltage source (Modified Nodal Analysis), references the ground node to 0 V, and solves A·x = b by Gaussian elimination with partial pivoting. Diodes and LEDs are non-linear, so their exponential I–V curve is linearised and re-solved with damped Newton–Raphson iteration until it converges. The circuit must contain a Ground to provide a voltage reference.
This free online electronic circuit simulator lets you build DC circuits with resistors, voltage sources, LEDs, switches, and current sources, then instantly solve node voltages, branch currents, and power dissipation using nodal analysis — all in your browser, no download required.
The simulator applies Modified Nodal Analysis (MNA) to solve your circuit. It assigns a voltage variable to every node, writes Kirchhoff's Current Law (KCL) equations at each node, and solves the resulting matrix system (Ax = b) for all unknown node voltages.
Once voltages are known, branch currents follow from Ohm's Law (I = V/R) and power from P = V²/R or P = I²R. This is the same algorithm used by professional SPICE-based simulators — just simplified for DC circuits and instant in-browser computation.
Resistors (any value in Ω, kΩ, or MΩ), independent voltage sources (DC), independent current sources (DC), LEDs and diodes (forward-biased threshold model), and open/closed switches. Wire up to 50 components and 30 nodes in a single schematic.
Each component has an editable Properties panel — click any element to change its value, label, or orientation. The probe tool lets you click any wire or node to read voltage and current in real time after pressing Run.
Voltage divider: two resistors in series from Vcc to GND — the midpoint voltage equals Vcc × R2/(R1+R2). LED current-limiting: a 5 V source, 330 Ω resistor, and LED in series — the simulator shows the 9.1 mA forward current.
Parallel resistors: two or more resistors between the same two nodes — total resistance equals 1/(1/R1 + 1/R2). Wheatstone bridge: four resistors forming a diamond — balance condition is R1/R2 = R3/R4. Load these from the 📚 Circuits library or build from scratch.
Professional SPICE simulators (LTspice, Multisim, Tina-TI) support transient analysis, AC sweep, noise analysis, and thousands of component models including BJTs, MOSFETs, and op-amps. This simulator targets DC steady-state analysis for students, educators, and engineers who need a quick sanity check without installing software.
For real IC design or PCB validation, use LTspice (free from Analog Devices) or the cloud-based Falstad circuit simulator. For learning fundamental circuit theory — KCL, KVL, Thevenin/Norton equivalents — this tool is the fastest way to verify your hand calculations.
Yes — completely free with a registered EngineersUniverse account. No download, no subscription, no credit card. The simulator runs entirely in your browser using JavaScript.
DC circuits with resistors, voltage sources, current sources, LEDs/diodes, and switches. You can build voltage dividers, current dividers, Wheatstone bridges, LED driver circuits, parallel/series networks, and any resistive network up to 30 nodes. AC circuits and reactive components (capacitors, inductors) are not currently supported.
Use nodal analysis: (1) choose a reference node (ground = 0 V); (2) write a KCL equation at each non-reference node — sum of currents leaving = 0; (3) express each current as (V_node - V_neighbor)/R; (4) solve the system of equations. The simulator does this automatically using matrix methods, but running through it manually is the best way to build intuition.
Common causes: (1) a voltage source with no return path to ground — every circuit needs a closed loop; (2) two voltage sources connected in parallel with different values (creates a contradiction); (3) a node with no resistive path to ground (floating node). Make sure every node connects back to GND through at least one resistor or voltage source.
Yes — it's ideal for checking circuit analysis problems from FE/PE practice exams. Build the circuit from the problem, run the simulation, and compare with your hand-calculated answer. It's especially useful for Thevenin equivalent circuits, maximum power transfer problems, and ladder networks.
A schematic tool (like KiCad or Eagle) captures the netlist for PCB layout — it draws the circuit but doesn't calculate voltages or currents. A circuit simulator (like this one, or SPICE) actually solves the equations and gives you numerical results. This tool does both: you draw the schematic and immediately get solved voltages and currents.
Yes — this is a free online circuit simulator that runs entirely in your browser, with nothing to install. Unlike desktop circuit simulation software (such as LTspice or Multisim), you just open the page, drag components onto the canvas, wire them, and click Run to solve the circuit. It works on any modern browser, including on a Chromebook or tablet.
Both terms apply: it is an electronic circuit simulator for component-level analysis (resistors, diodes, LEDs, transistors, op-amps) and an electrical circuit solver for DC networks — it computes the node voltages, branch currents, and power dissipation of the circuit you draw. "Circuit solver" simply refers to the math engine (here, Modified Nodal Analysis with Newton–Raphson for non-linear parts) that solves the circuit equations and returns numerical results.
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