AT Cycle 21

🔴❗ 2: W 1/22, 🟡❗ 4: W 1/22, 🔵❗ 8: W 1/22 - 1F capacitor lab (2)

Quiz on equivalent resistance (combo circuits) & Kirchhoff's Laws TODAY!

Safety Precautions:

• Have the teacher check your circuit before connecting the power supply.  

• Be mindful of the polarity of the electrolytic capacitor.  Remember that on the 1F electrolytic capacitor, the negative end has the stripes.

• Make sure all the knobs on the power supply are turned all the way counterclockwise before plugging in and turning on the power supply.

• Turn off the power supply when you are not actively taking data.

• Be sure to NOT touch any of the exposed wires in your circuit while you are running your experiment.

• Discharge your capacitor shortly after charging it to reduce the amount of time where you have a large amount of charge on your capacitor and to leave for adequate time for full discharge.  In general, minimize the time that you have an active circuit.  

• Make sure to discharge your capacitor fully before dismantling your circuit.

• At the end of the lab, unplug your power supply and place the plug on top of the power supply so I can see from across the room that it is unplugged.  

Homework:  If you have not completed the 1F capacitor lab, have a really good plan to do so quickly next class.  QUIZ Tuesday, January 28th on derivation of charging and discharging equations. 

🟥 2: F 1/24 lab, 🟨 4: Th 1/23 lab, 🟦 8: Th 1/23 lab - mystery capacitor lab 

Today, we will finish the one-farad capacitor lab, and I will verbally assess your understanding of the analysis.  

Then, we'll work on the Mystery Capacitor Lab to use what you know to see if you can determine unknown quantities in an RC circuit.  Make sure that you read the handout very carefully and explain everything!  Your grade will largely be based on  your ability to EXPLAIN what you did.  In this lab, we want to avoid trying to use just one or two data points to determine the values of the mystery capacitor and mystery resistor.  Why would this be a bad idea?  How can you use all of the hundreds of data points that you collected to get the best answer?  Use the power of Vernier software to help you solve this.

Safety Precautions:

• Have the teacher check your circuit before connecting the power supply.

• Be mindful of the polarity of the electrolytic capacitor.  The notch is on the positive end.  

• Make sure all the knobs on the power supply are turned all the way counterclockwise before plugging in and turning on the power supply.

• Turn off the power supply when you are not actively taking data.

• Be sure to NOT touch any of the exposed wires in your circuit while you are running your experiment.

• Discharge your capacitor shortly after charging it to reduce the amount of time where you have a large amount of charge on your capacitor and to leave for adequate time for full discharge.  In general, minimize the time that you have an active circuit.  

• Make sure to discharge your capacitor fully before dismantling your circuit.

• At the end of the lab, unplug your power supply and place the plug on top of the power supply so I can see from across the room that it is unplugged.  

We'll complete the lab by the end of the period and hand in the packet.  Then we'll do one problem to check for understanding.

    Required:  2007E1

Handout:  Mystery Capacitor Lab

Homework:  QUIZ Tuesday, January 28th on derivation of charging and discharging equations.  You should be done with the lab already, but if you have not done so yet, finish pages 1-2 of Mystery Capacitor Lab and plan out how you're going to quickly conduct the next part of the experiment outlined on page 3.  Read sections 27-3 & 27-4 in your textbook if you have not already done so.  Finish your lab and the above AP problem if you did not in class.  If you still don't know the physical significance of the time constant "RC", look it up!  It's important!  Watch the following videos:

❤️ 2: M 1/27, 💛 4: F 1/24, 💙 8: F 1/24 - RC circuits problems (1)

Today, to check your understanding of the previous mystery capacitor lab, do the following problems:   
Required 1:  2007E1, 2013E2, and Chapter 27 #59 & 60. 

If you need a refresher on how and why we linearize graphs for 2013E2, look at this basic guide on determining relationships from graphs.  This packet will not give you the exact function that you'll need, but if you think about the principles here, you can figure out how to linearize 2013E2. 

Then, rather than focusing on how capacitors charge and discharge over time, we'll think about what happens immediately after the switch is closed and a long time after the switch is closed.  For additional support, watch the following 3 videos.  

Remember that an uncharged capacitor acts like a wire and a fully charged capacitor acts like an open circuit.  Then think about using Kirchhoff's Loop Rule to solve the rest.  

Homework:  Watch the three videos above if you have not done so already.  QUIZ Tuesday, January 28th next class on derivation of charging and discharging equations.