In 1919, the 18th Amendment to the U.S. Constitution, which prohibited the sale and manufacture of alcohol, was ratified. It went into effect on January 16, 1920âbeginning the era known as Prohibition.
Because time constant calculations are important, and often needed, it is better to make the definition of the time constant (T) in a CR circuit: THE TIME TAKEN FOR THE VOLTAGE ACROSS A CAPACITOR TO INCREASE BY 63.2% OF THE DIFFERENCE BETWEEN ITS PRESENT AND FINAL VALUES.
1 Knowing the time constant allows us to estimate aspects of a response. 2  For example, a first order system with a time constant, t, will respond to a step input so that the system is within 5% of the final value in 3t seconds-i.e. three time constants. A first order system-with a single time constant-has a response that changes slope immediately after the step is applied. 2  The slope of this system does not change immediately, and the response seems to take a long time to get started.