Plot the characteristic curve of the zener diode in the reverse-breakdown region from the results obtained in step 1 of the procedure.
The Correct Answer and Explanation is :
To plot the characteristic curve of a Zener diode in the reverse-breakdown region, we first need to understand the relationship between the reverse voltage and current in this region. The reverse breakdown region is where the Zener diode operates in reverse bias and exhibits a significant current flow due to avalanche breakdown, which is the basis for the Zener diode’s voltage regulation property.
In the reverse breakdown region, once the reverse bias voltage exceeds a certain threshold (called the Zener voltage, (V_Z)), the current increases sharply even though the voltage remains nearly constant. This characteristic curve is typically flat after reaching the Zener voltage, indicating that the diode maintains a stable voltage regardless of the increase in current, as long as the current is within the safe operating limits.
Steps to plot the characteristic curve:
- Collect the Data: Measure the reverse current at various reverse voltages just below and above the breakdown voltage. Ensure that you gather data where the reverse current starts to increase rapidly.
- Plot the Data: The x-axis will represent the reverse voltage, and the y-axis will represent the reverse current. You will start from a low reverse voltage and plot until you reach the breakdown voltage, beyond which the current rises steeply.
- Identify the Breakdown Voltage: The Zener voltage (or breakdown voltage) is the point where the current increases sharply, signaling the diode entering the breakdown region.
Explanation:
In the reverse-biased condition, before the Zener voltage is reached, the current remains very small (typically in the nanoampere or microampere range). This is due to the relatively small reverse leakage current of the diode. However, once the voltage exceeds the Zener voltage, the diode enters avalanche breakdown, and the current starts to increase rapidly. The curve after this voltage appears flat, indicating the Zener diode’s ability to maintain a relatively constant voltage, despite an increase in current.
The reverse breakdown region is crucial for applications such as voltage regulation, where the diode stabilizes the voltage in the circuit by limiting the maximum voltage that can appear across it.
This behavior is what makes Zener diodes ideal for use in voltage clamping and protection circuits.
Let me know if you would like to see the plot based on any specific data you have!