what is the time constant of rl circuit
RL circuit These equations show that a series RL circuit has a time constant, usually denoted τ = L/R being the time it takes the voltage across the component to either fall (across the inductor) or rise (across the resistor) to within 1/e of its final value. That is, τ is the time it takes VL to reach V(1/e) and VR to reach V(1 − 1/e).
Second Though the historical definition of the unit was based upon this division of the Earth's rotation cycle, the formal definition in the International System of Units SI is a much steadier timekeeper: 1 second is defined to be exactly 9 192 631 770 cycles of a Caesium atomic clock.[1][2][3] Because the Earth's rotation varies and is also slowing ever so slightly, a leap second is added to clock time[nb 2] to keep clocks in sync with Earth's rotation.