Capacitor Charging
V(t) = V₀(1 − e^(−t/RC))
Voltage across a capacitor as it charges through a resistor.
Inductor Current
I(t) = I₀(1 − e^(−Rt/L))
Current through an inductor as it energizes in an RL circuit.
Op-Amp Inverting Gain
Aᵥ = −Rⁱ/Rᵢₙ
Closed-loop voltage gain of an inverting op-amp amplifier.
LED Current Resistor
R = (Vₛ − Vⁱ) / I
Series resistor needed to limit current through an LED.