Calculating Time Constants for RC and RL Circuits | Simple Physics Homework Help

In summary, the time constants for the two circuits can be calculated using the equations t=RC for an RC circuit and t=L/R for an RL circuit. In the first circuit, the time constant would be 0.09 seconds by adding the two resistors and multiplying by the capacitance. In the second circuit, the time constant would be 0.0022 seconds by calculating the parallel resistance of the two resistors and dividing it by the inductance. The order of the resistors does not matter in the first circuit as they are in series. Both of your attempts were correct.
  • #1
jayz618
27
0

Homework Statement



Calculate the time constants of the following circuits

I drew them in the attachment


Homework Equations



t=RC in a RC Circuit

t= L/R in a RL Circuit







The Attempt at a Solution



Im not sure if in the first one, I would simply add the two resistors and multiply the total by the Capacitance ?

If so, then it would be 45 k Ohm x 2 Micro Farads = 45000 Ohms x 2E-6 Farads = .09 Seconds


The second one, I calculated the value of the parralell resistors as 30 ohm x 80 ohm / 110 ohm = 21.81 Ohms

Then it would just be 50 milliHenries = .05 Henries / 21.81 Ohm = .0022 Seconds
 

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  • #2
Correct.
 
  • #3
For the first one, it doesn't matter that the second resistor comes after the capacitor ?
 
  • #4
It doesn't matter. The resistors are in series. Whatever charges move through one resistor, have to go through the other.
 
  • #5
Cool, so I was correct on both attempts ? Good News




Thanks
 

1. What is a simple time constant?

A simple time constant is a measure of the time it takes for a system to reach a specific state or level after a change in a particular variable. It is commonly used in science and engineering to describe the dynamics of a system.

2. How is a simple time constant calculated?

The formula for calculating a simple time constant is T = RC, where T is the time constant, R is the resistance of the system, and C is the capacitance. This formula can be used for systems that follow an exponential decay or growth pattern.

3. What is the significance of a simple time constant?

Simple time constants are important because they allow us to predict how a system will respond to a change in a particular variable. They also provide insights into the stability and behavior of a system.

4. How is a simple time constant used in real-life applications?

Simple time constants are used in a variety of real-life applications, such as electronic circuits, chemical reactions, and biological processes. They can also be used in modeling and predicting natural phenomena, such as population growth or weather patterns.

5. Are there any limitations to using simple time constants?

Yes, there are limitations to using simple time constants. They are only accurate for systems that follow an exponential decay or growth pattern, and they do not take into account external factors that may affect the system's behavior. Additionally, they may not be applicable for highly complex systems with multiple variables.

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