Interactive schematics / 26 tools
Circuit Design
Move from electrical fundamentals and resistor networks to timing, control logic, analog circuits, and practical power supplies.
Fundamentals
Ohm's Law Calculator
Find voltage, current, or resistance from the other two - the one relationship every circuit obeys.
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Voltage Divider Calculator
Two resistors in series split a voltage in proportion to their size - the trick behind most sensor circuits.
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RC Time Constant Calculator
How fast a resistor and capacitor charge or discharge together, boiled down to one number: tau.
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Capacitive Reactance Calculator
See how much a capacitor resists AC current at a given frequency - resistance's frequency-dependent cousin.
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LED Series Resistor Calculator
The one calculation every LED circuit needs, so the LED lights up instead of burning out.
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Battery Life Calculator
Estimate how many hours a battery will actually power a project once real-world efficiency is factored in.
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RMS Voltage Calculator
Convert an AC signal's peak voltage into the steady DC-equivalent value that actually does the work.
Open tool →Resistors & Networks
Resistor Color Code Calculator
Turn four color bands into an exact resistance and tolerance, with a picker instead of a chart to squint at.
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5-Band Resistor Color Code Calculator
The same idea with one more digit of precision - for the tighter-tolerance resistors that use five bands.
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Series Resistor Calculator
Add resistors end to end and their resistances just add up. Enter a few values, get the total.
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Parallel Resistor Calculator
Wire resistors side by side and the math flips - flip each value, add them, flip the sum back.
Open tool →Timing, Filters & Analog Design
555 Timer Astable Circuit Calculator
Set two resistors and a capacitor to tune a free-running 555 timer's frequency and duty cycle.
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555 Timer Monostable Circuit Calculator
One trigger, one pulse - work out exactly how long a 555 timer's one-shot output stays high.
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High Pass Filter Calculator
Find the cutoff frequency of an RC filter that lets highs through and blocks the lows.
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Low Pass Filter Calculator
The same RC pair, wired the other way round - keep the lows, roll off everything above the cutoff.
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Op-Amp Gain Calculator
Two resistors decide how much an op-amp amplifies a signal - and whether it flips polarity on the way.
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Air-Core Coil Designer
Estimate a single-layer coil from its dimensions, inspect the winding, and check whether the turns fit.
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LC Resonance Designer
Choose a target frequency and capacitor to size an ideal LC tank, with a winding-loss Q estimate.
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Band-Pass Filter Designer
Design a buffered RC band-pass circuit and compare stage corners with the complete frequency response.
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Cascaded Op-Amp Gain Designer
Build an inverting or non-inverting multi-stage amplifier, see total gain, and compare common op-amp ICs.
Open tool →Control Design
Power Conversion & Supplies
SMPS Design
Explore AC-mains and DC-input isolated flyback supplies, calculate a first-pass DCM operating point, and follow energy through an interactive circuit.
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Full-Wave Bridge Rectifier Designer
Estimate rectified DC voltage, ripple frequency, reservoir capacitance, and diode stress for a low-voltage supply.
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Linear Regulator Stability Designer
Estimate heat, efficiency and voltage headroom; document capacitor and ESR requirements without a false stability verdict.
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Buck Converter Designer
Estimate duty cycle, inductor, output capacitor, ripple current, peak current, and estimated total power loss.
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