# AT Cycle 22

## 1/24 - 1/27

M 1/24

T 1/25

W 1/26

Th 1/27

### π΄β 1: M 1/24, π‘β 3: M 1/24 - breadboard

Quiz on equivalent resistance (combo circuits) and Kirchhoff's Law TODAY!

Today, start a lab to learn about the circuits equipment we have available to us in order to measure the voltage and current "through" a capacitor. In particular, you'll learn how to build an RC circuit with a 1F capacitor breadboard. This is a warm up for your big formal lab next lab period, so make sure you understand this one!

Then we'll do one problem to check for our understanding.

Required: 2007E1

Homework: Read sections 27-3 & 27-4 if you haven't already. Rewatch Jon's video on charging and discharging capacitors if you feel like you need to. QUIZ Friday, January 28th on derivation of charging and discharging equations (marking period 3). Watch the following video on energy stored in capacitors:

### π₯ 1: W 1/26 lab, π¨ 3: T 1/25 lab - One Farad Capacitor Lab

Last time, we learned about how to use a breadboard to build a circuit. Today, we'll actually build a practice circuit using the 1F capacitor. You will have to pick your own value for a charging/discharging resistor. Then, using the data you collect from Vernier LoggerPro, verify the time constant with two different methods. Evaluate which method you think would be better.

Equipment: breadboard, wiring box, resistor of your choice, 1F capacitor, DC power supply, Vernier Differential Voltage probe, Vernier Current or High Current Sensor probe (check what you think the max current will be in your circuit), computer with LoggerPro software.

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 the power supply.

• 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: QUIZ Friday, January 28th on derivation of charging and discharging equations (marking period 3). If you have not done so yet, finish pages 1-2 of Mystery Capacitor Lab and plan out how you're going to 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.

### β€οΈ 1: Th 1/27, π 3: W 1/26 - mystery capacitor lab (1)

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.

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 the power supply.

• 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.

Then we'll do one problem to check for understanding.

Required: 2007E1

Handout: Mystery Capacitor Lab

Homework: If you have not done so yet, finish pages 1-2 of Mystery Capacitor Lab and plan out how you're going to 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 video on Dielectrics in Capacitors below, although it should be review of what we have already talked about in class, so at least skip through it.