We designated the value of time it takes for io to drop from unity to zero, assuming a constant rate of decay, by the greek letterτ R f-t=l or T =L/R--time-constant i(t=loe t ori(z)=0.36810=36810% The value of io at tT =er=e=0.368 i/I In one time constant the response has dropped to 36.8 0.368 percent of its initial value. 0.135 T 2t 3TWe designated the value of time it takes for i/I0 to drop from unity to zero, assuming a constant rate of decay, by the Greek letter .  The value of i/I0 at t=  0.368 ( ) 1 0 = = = − − e e I i    In one time constant the response has dropped to 36.8 percent of its initial value. If =1 or =  L/R--time-constant L R   t i t I e −  = 0 ( ) 0 0 0 8 0 or i( ) = 0.368I = 36. I 0.368 t 0 0 i / I  2 3 0.135 0.051