LED Series Resistor Calculator
Compute the value (and minimum power rating) of the current-limiting resistor needed to safely drive an LED at a chosen...
Compute the value (and minimum power rating) of the current-limiting resistor needed to safely drive an LED at a chosen...
Compute the remaining quantity after time t for an exponentially decaying process N(t) = N₀ · e⁻ᵏᵗ, plus the half-life.
Find the hypotenuse from two legs, or recover a missing leg from the hypotenuse and the other leg, using the Pythagorean...
Calculates serve statistics including first-serve %, points won on 1st/2nd serve, ace rate, and estimated hold % from se...
Compute the rest energy equivalent of a mass using Einstein's mass-energy equivalence E = mc².
Compute the 2-class softmax probabilities (positive vs negative) from raw logits z₁ and z₂: p_i = exp(z_i) / [exp(z₁) +...
Compute probabilities of single events, joint events, and complements using basic probability rules.
Estimate the pH of a buffer solution from the pKa of the weak acid and the molar ratio of conjugate base to acid.
Calculates annual water consumption and electricity cost of a washing machine from loads per week, water usage per load,...
Compute a normal-approximation (Wald) confidence interval for a sample proportion, given the sample proportion p̂, the s...
Estimates the maximum mortgage loan a household can afford from their maximum monthly payment, interest rate, and loan t...
Compute the frequency observed by a stationary observer when a source moves at velocity v_s, using the classical Doppler...
Every "X% of Y" problem, every "what percent of", every percent-change question — written out the way you'd actually say them.
Standard deviation is "average distance from the average". That one sentence covers 90% of everything you ever need to remember about it.