The Reference Shelf for Your Electronics Bench
Calculators that draw the circuit, pinouts for the boards you actually own, and the charts everyone ends up needing at step three of a project.
Ohm's law calculator
Type two values and watch the circuit solve the rest: volts, amps, ohms and watts.
Parallel resistor
The current splits, the math doesn't have to. Two resistors or ten, one combined value.
Voltage divider
Two resistors turn 12 V into the 5 V you needed, and the diagram shows where to tap it.
Resistor color code
Click the bands you see, read the value. Works with 4-band and 5-band resistors.
Wire gauge
How many amps a wire carries before it minds. Pick the gauge for your load and length.
555 timer designer
Astable or monostable: pick the blink rate and get the resistor pair, capacitor and pinout.
More calculators
- LED series resistorthe resistor that keeps an LED alive
- Capacitor code104 on the case, 100 nF in the circuit
- SMD resistor codethree digits on a grain of rice
- Battery lifecapacity against draw, in hours
- RC time constantcharge time and filter cutoff
- Ohm's law wheelthe 12-formula wheel, tap what you need
Charts and Tools
The tables worth printing and taping inside the parts cabinet door, plus the tool for parts you cannot name.
- What component is this?a few questions and drawings identify the mystery part
- AWG wire chartdiameter, resistance and ampacity per gauge
- Standard resistor valuesE12, E24 and E96 series
- Capacitor conversion tablepF, nF and uF without counting zeros
- Schematic symbolswhat every squiggle means
- Battery sizesfrom AAA to coin cells
Pinouts
Pick the category, then the exact board or plug, since an "ESP32" can be a dozen different modules.