⌁BenchSupply

Electronics calculators

Clear units. Quick checks.

Ohm’s law solve any missing value

Enter exactly two positive values. Simple DC / resistive-load arithmetic.

LED resistor resistance and rating

Use one resistor per parallel LED string. Check the LED data sheet.

Voltage divider output, current, dissipation

Unloaded output only. A load changes the answer.

Battery runtime usable watt-hours

Actual runtime varies with load, temperature, age and cutoff voltage.

Resistor colour code four-band decoder
555 astable frequency and duty cycle

Standard astable approximation; component tolerance changes real timing.

RC timing time constant and cutoff

τ = RC. A real load can change the result.