Electronics Circuit Designer — Live Simulation Free
Place components, draw wires, run simulation. Detects short circuits, calculates voltage & current, animates current flow. 15+ components from LED to voltage regulator.
Free Online Circuit Designer — 15 Components, Live Simulation, Short Circuit Detection
Electronics circuit design used to require expensive software like Multisim, LTspice, or Proteus. Students in most parts of the world couldn't access these tools freely. This browser-based designer changes that — place components on a grid, connect them with wires, run the simulation, and get instant feedback on whether your circuit works, what voltages are present, and whether you've accidentally created a short circuit.
How the Live Simulation Works
When you click Simulate, the tool runs a simplified nodal analysis on your circuit. It traces the connections from each power source, calculates the voltage at each node using Kirchhoff's Voltage Law (KVL), and determines current through each branch using Kirchhoff's Current Law (KCL). Components like resistors, LEDs, diodes, and transistors affect this calculation based on their properties. The animated current flow shows electrons moving through the circuit — faster animation means higher current.
Components Available — From Basic to Advanced
- Voltage Regulator (7805/7812): Takes 8–35V unregulated input, outputs a clean 5V or 12V. Fundamental to most power supply designs. Use with input/output capacitors for stability.
- Transistor (NPN/PNP BJT): Three-terminal device for switching and amplification. NPN conducts when base is high, PNP conducts when base is low. Current gain (hFE) of 100–500 typical.
- MOSFET: Voltage-controlled switch. N-channel conducts when gate voltage exceeds threshold (typically 2–4V). Preferred over BJT for power switching applications.
- Op-Amp: High-gain differential amplifier. Used in comparator, inverting/non-inverting amplifier, and filter configurations. LM741 and LM358 are common ICs.
- Zener Diode: Conducts in reverse above its breakdown voltage (Vz). Used for voltage reference and regulation. Common values: 3.3V, 5.1V, 6.8V, 12V.
- Transformer: Steps AC voltage up or down. Ratio determines output voltage. Fundamental in mains-to-DC power supply design before rectification.
- Relay: Electrically controlled mechanical switch. Low-current control signal switches high-current load. Allows microcontrollers to control mains voltage safely.
Simple Inverter Circuit — How to Build It
A simple DC inverter converts battery voltage to AC. The basic topology uses transistors or MOSFETs in a push-pull configuration driven by an oscillator (typically 555 timer at 50Hz or 60Hz). Load the "Simple Inverter" preset from the sidebar to see a simplified version, then modify the transistor type and transformer ratio for your target voltage.
Voltage Regulator Circuit — 7805 Walkthrough
The 7805 voltage regulator requires just three components beyond the IC itself: an input capacitor (0.33μF), an output capacitor (0.1μF), and a ground connection. Input: 7.5–25V DC (unregulated). Output: clean 5V up to 1.5A. Load the 7805 preset to see the complete circuit, then change component values to observe how the simulation responds.
❓ FAQ
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