Phase difference in CR and LR circuits

[cash200107]

I have just done an experiment on CR and LR circuits.
http://img9.picsplace.to/img9/21/RC.jpg

Connect channel 1 of the CRO across both the capacitor and resistor and channel 2 across the resistor.The trace on channel 1 is taken as the p.d. across the capacitor and that on channel 2 as ths current throught the capacitor.
http://img9.picsplace.to/img9/21/RL.jpg

Replace the capacitor waith a high inductance coil fitted on a double C-core.

I have some questions about this.

1.Why is channel 1 is connected across both the capacitor and resistor and not only the capacitor?

2.Why the trace on channel 2 gives the current through the capacitor?

3.When we increased the resistance value, the phase difference decreased.Why?

4.what is the phase difference between the p.d. and the current?

5.Change the resistance value and observe how this affects the phase
difference.Describle and explain the change,if any,in the phase difference.

6.Replace the capacitor with a high inductance coil fitted on a double c-core.Observe the CRO traces and note the phase diff between the p.d. across the inductor and the current through it.What is the phase diff. between the p.d. and the current?Why is it not 90°? How to sketch the CRO traces?

7.Change the resistance value and observe how this affects the phase difference.Describle and explain the change, if any, in the phase difference.

I have so many question to ask ..

 

[Mindscrape]

I'm not going to do your homework for you. What, specifically, do you need help with?

Phasers seem like the way to go with this type of problem, though since there isn't anything numerical you don't necessarily have to.

 

[m2003]

I am happy to address your questions about phase difference in CR and LR circuits. First, let me explain the setup of the experiment. The phase difference is a measure of the time delay between the voltage and current in an AC circuit. In order to measure this, we use an oscilloscope (CRO) to display the voltage and current waveforms.

1. Channel 1 is connected across both the capacitor and resistor because in a CR circuit, the voltage across the capacitor and resistor are related and both contribute to the overall phase difference. By connecting channel 1 across both components, we can see the combined effect on the phase difference.

2. The trace on channel 2 gives the current through the capacitor because, in a CR circuit, the current through the capacitor is the same as the current through the resistor. This is known as Kirchhoff's Current Law.

3. When the resistance value is increased in a CR circuit, the phase difference decreases. This is because increasing resistance causes the voltage and current to become more in phase.

4. The phase difference between the p.d. and current is the angle difference between the voltage and current waveforms. It is typically measured in degrees or radians.

5. Changing the resistance value in a CR circuit will affect the phase difference. As mentioned before, increasing resistance will decrease the phase difference, while decreasing resistance will increase the phase difference. This is due to the relationship between voltage and current in a CR circuit.

6. When the capacitor is replaced with a high inductance coil fitted on a double C-core, the phase difference between the p.d. and current will not be 90°. This is because in an LR circuit, the voltage and current are not in phase. The CRO traces will show a phase difference between the voltage and current waveforms, but it may not be a perfect 90° angle. To sketch the CRO traces, you can use a protractor to measure the angle between the two waveforms.

7. Similar to the CR circuit, changing the resistance value in an LR circuit will also affect the phase difference. However, in an LR circuit, increasing resistance will increase the phase difference, while decreasing resistance will decrease the phase difference.

I hope this helps to clarify any questions you may have about phase difference in CR and LR circuits. Keep exploring and asking questions, that's what makes a great scientist!