Pre-lab 3 RC Circuit

Pre-lab 3 RC Circuit - The time constant RC has the...

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1. What is the meaning of the time constant, RC? The time constant, RC, is a characteristic of all exponential curves and gives an indication of the rate of change of the current. It indicates, for an exponential situation, the length of time required for the charging or discharging of a certain amount occurring over a finite time. 2. Why isn’t the time constant defined to be the time it takes the capacitor to fully charge or discharge? The time constant is defined to be the time it takes for a significant change in charge to occur, rather than a full charging or discharging because a capacitor takes an exponentially long time to fully charge. In fact, it takes an infinite amount of time until the capacitor is practically completely charged. 3. Show that RC has units of time.
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Unformatted text preview: The time constant RC has the components R in ohms (volts over coulomb per second ) and C in Farad (coulomb/volt). Multiplying the two units gives volts*second*coulomb/coulomb*volt = seconds 4. Explain conceptually why the time constant is larger for increased resistance. A larger resistance increases the time it takes for a capacitor to charge. A resistor represents an area of potential drop in a circuit, with a larger resistance equating to a greater drop in potential. This resultant potential drop allows less of a charge to be exerted on the capacitor plates and therefore the capacitor will take a longer time to charge. 5. What does an oscilloscope measure? Oscilloscopes measure the voltages in a circuit and how they vary over time....
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This note was uploaded on 11/27/2011 for the course PHYS 105 taught by Professor Walker during the Fall '08 term at UNC.

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