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.
In a series circuit, the voltage across a resistor is directly proportional with its resistance (Et= I(Rint+R). That means in a series circuit the voltage across the resistor will increase when the resistance in increased, while the current will reduce. A power source has internal resistance (Rint) which will be in series with the resistor R. So even though your resistor is connected across the power supply, the internal resistance Rint is in series with it.