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.
If a system has atime constant of 3.2 microseconds, then the settling time in response to a step input will be 12.8 microseconds, or if thetime constant is 1.6 days, then the settling time will be 6.4 days. The time constant of the open-loop system serves asa scale factor for the time-domain characteristics. Normalizing the time by the time constant allows the characteristics of the response to be shown without worryingabout the actual time scale. This will be particularly useful in the study of second-order systems where there are twodesign parameters in the transfer function.