Calculators
Component calculators for everyday design work. Each one solves in both directions, prints every step of the arithmetic so you can check it, and finishes at the nearest standard part value with the error that choice costs you.
Categories marked soon are mapped out and on the way.
Circuit fundamentals
The arithmetic every design leans on, whatever it is for.
- Passive networksResistors, capacitors and inductors combined in series, parallel and mixed networks. Solves in both directions and ends at a standard part value.
- Ohm's law and powerThe four-way relationship between voltage, current, resistance and power, and what it implies for part ratings and heat.
- Dividers and referencesGetting a specific voltage or current out of a supply you already have — including what happens once a real load is attached.
- Filters and time constantsRC and RL time constants, corner frequencies, and the first-order filters that most real designs actually use.
Power and semiconductors
Driving, switching and regulating — where parts get hot and die.
- Batteries and runtimeHow long a design lasts on a given cell, and what the pack has to be to get there — including the sag and the derating that make the number on the label optimistic.
- LEDs and driversSeries resistors, arrays and constant-current drivers, with forward-voltage spread treated as the variable it really is.
- Transistors and diodesBiasing, switching and protection with BJTs, MOSFETs and diodes — the arithmetic that decides whether a part survives.
- Power suppliesLinear and switching regulators, rectifiers and bulk capacitance, from ripple to thermal headroom.
- MagneticsInductors and transformers from first principles: turns, core geometry, saturation and coupling.
Layout, signals and reference
Getting a design onto a board, and the numbers you look up doing it.
- PCB and thermalTrace geometry, current capacity, impedance and getting heat off the board.
- Signals and decibelsLevels, gain, noise and the several different things people mean when they say "dB".
- Standard values and codesThe values real parts actually come in, and how to read the markings on them.
- Unit conversionsSmall, single-purpose conversions that come up constantly and deserve to be fast.