# Why is Channel 1 Connected Across CR and LR Circuits?

• momomo_mo
In summary, when using an oscilloscope to measure voltage across a capacitor and current through it, channel 1 is connected across both the capacitor and resistor in order to avoid grounding two different points in the circuit. This allows for accurate measurement of the voltage across the capacitor.
momomo_mo
Assume there is a capacitor and resistance connecting in series in a.c. Now channel 1 of the CRO acroos both the capaciotr and resistor and channel 2 across the resistor.The trace on channel 1 was taken as the p.d. across the capacitor and that on channel 2 as the current through the capacitor.
But I want to know why channel 1 is connected across both the capacitor and resistor and not only the capacitor?

Thank You

Most oscilloscopes measure from ground to the probe tip. If you connected one probe across the resistor and the other across the capacitor, you'd ground two different points in your circuit which would give you bad results at best or melt something at worst. So you connect both grounds together at one point, at the bottom of the resistor in your case, and the probe tips to the tops of the R and C. The difference between the two channels gives pure voltage across C.

for your question. The reason why channel 1 is connected across both the capacitor and resistor is because in an AC circuit, the voltage across the capacitor and the current through the capacitor are out of phase with each other. This means that the voltage and current waveforms do not align perfectly on the same axis. By connecting channel 1 across both components, we are able to measure the voltage and current at the same time and see the phase difference between them. This is important in understanding the behavior of the circuit and how the capacitor is affecting the current flow. If we were to only connect channel 1 across the capacitor, we would not be able to accurately measure the voltage and current relationship. Therefore, by connecting channel 1 across both components, we can gather more comprehensive data and analyze the circuit more effectively. I hope this answers your question.

## 1. Why do we need to connect Channel 1 across both CR and LR circuits?

Connecting Channel 1 across both CR and LR circuits allows us to measure both the resistance and inductance of a circuit at the same time. This gives us a more comprehensive understanding of the circuit's behavior.

## 2. Can't we just measure the resistance and inductance separately?

While it is possible to measure the resistance and inductance separately, connecting Channel 1 across both CR and LR circuits allows for more accurate and efficient measurements. It also eliminates the need to switch between different probes or instruments.

## 3. What is the advantage of using Channel 1 instead of separate channels for CR and LR circuits?

Using Channel 1 allows us to observe the relationship between resistance and inductance in a circuit, which is important for understanding its behavior. It also simplifies the measurement process and reduces the chances of error.

## 4. Is it necessary to connect Channel 1 across both CR and LR circuits for every circuit?

No, it is not necessary for all circuits. This method is most useful for circuits with both resistance and inductance, such as inductors or circuits with complex impedance. For simple circuits with only resistance or inductance, it may not be necessary to use Channel 1.

## 5. Can we use Channel 1 to measure capacitance as well?

No, Channel 1 is specifically designed to measure resistance and inductance. To measure capacitance, a separate channel or instrument is needed. It is also not recommended to connect Channel 1 to a circuit with capacitance as it can cause inaccurate readings and potential damage to the equipment.

• Introductory Physics Homework Help
Replies
20
Views
661
• Introductory Physics Homework Help
Replies
5
Views
474
• Introductory Physics Homework Help
Replies
3
Views
746
• Introductory Physics Homework Help
Replies
3
Views
435
• Introductory Physics Homework Help
Replies
8
Views
404
• Introductory Physics Homework Help
Replies
4
Views
2K
• Introductory Physics Homework Help
Replies
14
Views
811
• Introductory Physics Homework Help
Replies
6
Views
2K
• Introductory Physics Homework Help
Replies
3
Views
1K
• Introductory Physics Homework Help
Replies
5
Views
2K