Question

Draw a block diagram of CRO and state the function of each block.

Answer 1

A Cathode Ray Oscilloscope (CRO) is an electronic instrument used to display and analyze the waveform of electronic signals. It consists of several key components, each serving a specific function. Below, I'll describe the block diagram of a CRO and explain the function of each block.

### Block Diagram of a CRO

```
+------------------+
|    Input Stage   |
|    (Probes)      |
+------------------+
          |
          v
+------------------+
|   Vertical Amp   |
+------------------+
          |
          v
+------------------+
|    Time Base     |
+------------------+
          |
          v
+------------------+
|   Horizontal Amp  |
+------------------+
          |
          v
+------------------+
|   CRT (Display)  |
+------------------+
```

### Functions of Each Block

1. **Input Stage (Probes)**:
   - **Function**: The input stage consists of probes that connect to the circuit or signal source. They are responsible for capturing the electrical signals that will be analyzed.
   - **Details**: Probes often have attenuation features to protect the CRO from high voltages and to provide accurate measurements without loading the circuit.

2. **Vertical Amplifier**:
   - **Function**: The vertical amplifier increases the amplitude of the input signal to a level that can be processed further.
   - **Details**: This block controls the vertical deflection of the electron beam in the CRT. It scales the input signal based on the selected voltage/division setting, allowing the user to visualize signals with varying amplitudes.

3. **Time Base**:
   - **Function**: The time base generates a ramp signal that controls the horizontal movement of the electron beam across the screen.
   - **Details**: It determines how fast the electron beam sweeps across the screen, allowing for different time scales to be selected (e.g., microseconds per division). This is crucial for analyzing the time-domain characteristics of signals.

4. **Horizontal Amplifier**:
   - **Function**: This block further amplifies the ramp signal generated by the time base to control the horizontal deflection of the electron beam.
   - **Details**: The horizontal amplifier ensures that the sweep speed is adequate for the selected time base, enabling accurate visualization of periodic signals and their timing relationships.

5. **CRT (Cathode Ray Tube)**:
   - **Function**: The CRT is the display unit of the CRO, where the waveform is visualized.
   - **Details**: It contains an electron gun that shoots a beam of electrons towards a phosphorescent screen. The beam is deflected by the signals from the vertical and horizontal amplifiers, resulting in a visible waveform. The intensity of the beam can also be controlled, affecting how brightly the waveform appears.

### Summary

In summary, the block diagram of a Cathode Ray Oscilloscope illustrates the flow of an electrical signal from its input stage through various amplification and timing components before it is displayed on the CRT. Each block plays a critical role in ensuring that the user can accurately observe and analyze electronic waveforms, making the CRO an essential tool in electronics testing and development.

Answer 2

Certainly! A Cathode Ray Oscilloscope (CRO) is a versatile electronic instrument used to display and analyze the waveform of electronic signals. It has several key components that work together to provide a visual representation of these signals. Here's a detailed block diagram of a typical CRO and the function of each block:

### Block Diagram of a Cathode Ray Oscilloscope (CRO)

```
+--------------------+    +-------------------+    +---------------------+
| Signal Input       |    | Vertical Deflection|    | Cathode Ray Tube    |
|                    |    | System             |    | (CRT)               |
+--------+-----------+    +----------+--------+    +----------+----------+
         |                           |                       |
         |                           |                       |
         |                           v                       |
         |                     +-----+-----+                 |
         |                     |  Amplifier |                 |
         |                     +-----+-----+                 |
         |                           |                       |
         |                           |                       |
         |                           v                       |
         |                  +--------+--------+              |
         |                  |    Time Base     |              |
         |                  |     (Horizontal  |              |
         |                  |    Deflection)   |              |
         |                  +--------+--------+              |
         |                           |                       |
         |                           |                       |
         |                           v                       |
         |                 +---------+----------+            |
         |                 |     Sweep Circuit   |            |
         |                 +---------+----------+            |
         |                           |                       |
         |                           |                       |
         |                           v                       |
         |                 +---------+----------+            |
         |                 |   Trigger Circuit   |            |
         |                 +---------+----------+            |
         |                           |                       |
         |                           |                       |
         |                           v                       |
         |                 +---------+----------+            |
         |                 |   Display (CRT)     |            |
         |                 +---------------------+            |
         |                                                   |
         |                                                   |
         |                                                   |
         |                                                   |
         +---------------------------------------------------+
```

### Functions of Each Block

1. **Signal Input**
   - **Function:** The signal input block receives the electronic signal from a test point or device under examination. This is the point where you connect the probe or input cable of the CRO.

2. **Amplifier**
   - **Function:** The amplifier increases the amplitude of the incoming signal to make it suitable for further processing. This step is crucial if the signal's amplitude is too low to be accurately displayed.

3. **Vertical Deflection System**
   - **Function:** The vertical deflection system controls the vertical movement of the electron beam in the CRT. It translates the input signal’s amplitude into vertical deflection on the screen. Essentially, it plots the signal's voltage against time.

4. **Time Base (Horizontal Deflection)**
   - **Function:** The time base controls the horizontal movement of the electron beam. It determines how fast the beam moves horizontally across the screen, thus setting the time scale for the waveform display. This helps in analyzing the signal's frequency and time characteristics.

5. **Sweep Circuit**
   - **Function:** The sweep circuit generates a time-based ramp signal that drives the time base. It ensures that the electron beam sweeps across the screen in a controlled manner, creating a stable and repetitive display of the waveform.

6. **Trigger Circuit**
   - **Function:** The trigger circuit stabilizes the waveform display by synchronizing the sweep circuit with the input signal. It ensures that the waveform starts at a consistent point, allowing for a steady and repeatable display.

7. **Display (CRT)**
   - **Function:** The Cathode Ray Tube (CRT) is the final component where the waveform is visualized. The electron beam is directed to strike the phosphorescent screen, creating a visible trace that represents the waveform of the input signal.

### Summary

- **Signal Input:** Where the signal is introduced.
- **Amplifier:** Boosts the signal’s amplitude.
- **Vertical Deflection System:** Controls vertical positioning based on signal amplitude.
- **Time Base:** Controls the horizontal sweep based on time.
- **Sweep Circuit:** Generates the time-based ramp for the time base.
- **Trigger Circuit:** Synchronizes the waveform display.
- **Display (CRT):** Visualizes the waveform on the screen.

Each block plays a crucial role in ensuring that the CRO accurately displays the waveform of the input signal for analysis.