👩‍🏫
CHAMUNDI
AI Laboratory Teacher
EXPERIMENT 06
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GopalKrishna Advanced Rural Research Foundation

GARRF Virtual Engineering & Electronics Laboratory

KALAM ZERO RESEARCH FUNDING LAB

EXPERIMENT 06 ZENER DIODE V-I CHARACTERISTICS VOLTAGE REGULATION

⚡ Experiment 06 — Zener Diode Characteristics & Voltage Regulation

A Zener diode is a specially designed semiconductor diode that is commonly operated in reverse breakdown to provide a relatively stable reference or regulated voltage.

🎯 Experiment Objective

To study the V–I characteristics of a Zener diode in forward and reverse bias, identify the Zener breakdown region and investigate its use as a simple voltage regulator.

👨‍🎓 Think Before You Start
  • Why can a Zener diode safely operate in reverse breakdown while an ordinary diode is normally not operated there?
  • What happens to the Zener current when the input voltage increases?
  • Why is a series resistor necessary in a Zener regulator?
  • Will the regulated output remain exactly constant for every possible input voltage?

📚 1. Theory

What is a Zener Diode?

A Zener diode is a semiconductor diode designed to operate in the reverse-bias breakdown region. When the reverse voltage reaches a specified value called the Zener voltage, the diode current can change substantially while the voltage across the device changes relatively little.

Zener Breakdown

The reverse characteristic contains a region in which the Zener voltage remains comparatively stable while reverse current increases. This property makes the device useful for voltage regulation and reference circuits.

VZ ≈ constant in the regulation region

Zener Regulator

A simple Zener regulator normally contains a series resistor and a Zener diode connected across the load. The resistor limits current and absorbs the difference between the input and regulated voltage.

IS = (VIN − VZ) / RS
IS = IZ + IL

where IZ is the Zener current and IL is the load current.

🧩 2. Select Experiment Mode

🟢 Ready. Configure the Zener diode and begin the experiment.

🔬 3. Virtual Zener Circuit

⚡ 4–6. LIVE ZENER V–I MAGIC WORKSPACE

Press ▶ AUTOMATIC CHARACTERISTIC SCAN and watch the circuit measurements and Zener V–I curve develop together in real time.
🔬 Section 4 — Live Measurements
Input Voltage0.00 V
Zener Voltage0.00 V
Zener Current0.00 mA
Load Current0.00 mA
Series Current0.00 mA
Regulation StatusOFF
🟢 Ready — start the automatic scan.
What to watch: before breakdown, Zener current is very small. Near the selected Zener voltage, the current begins to rise while the Zener voltage stays comparatively stable.
📈 Sections 5–6 — Zener V–I Characteristic

The blue trace is the live reverse characteristic being built during the scan. The orange marker identifies the selected Zener voltage; the red point is the present operating point.

📐 5. Voltage Regulation Monitor

Input0.00 V
Output0.00 V
Zener Current0.00 mA
Load Current0.00 mA
Regulation Error0.00 %

🔬 7. Engineering Analysis

Start the experiment to generate the engineering analysis.

📝 8. Student Observation Table

Set different input voltages and use ADD OBSERVATION to record the readings.

Trial VIN VZ IZ IL Status

🎯 9. Identify the Zener Breakdown Region

Increase the input voltage. The simulator will identify when the Zener enters its regulation region.

🎓 10. Experiment Conclusion

Complete the experiment to observe the Zener breakdown characteristic and voltage regulation behaviour.

❓ 11. Student Quiz

Q1. A Zener diode is normally used for voltage regulation in:
Q2. The main purpose of the series resistor in a simple Zener regulator is to:
Q3. VZ represents:
Q4. When a Zener is operating in its regulation region, the output voltage is approximately:
Q5. Increasing the series resistance generally causes the available current to:

🤖 CHITTI

GARRF Robotics & Engineering AI Mentor

Need help understanding Zener breakdown or voltage regulation? Ask CHITTI.

💡 Try asking:

"What is Zener breakdown?"

"Why does a Zener diode work as a voltage regulator?"

"Why is the series resistor required?"

"What happens when the load resistance changes?"

"What is the difference between an ordinary diode and a Zener diode?"

👨‍🎓 12. How to Perform Experiment 06

  1. Select a Zener voltage, for example 5.1 V.
  2. Choose a suitable series resistance.
  3. Start the input voltage at zero.
  4. Increase the input voltage gradually.
  5. Observe the Zener voltage and current.
  6. Identify the point where reverse regulation begins.
  7. Record several voltage and current readings.
  8. Change the load resistance and observe the regulated output.
  9. Compare the output voltage with the nominal Zener voltage.
  10. Complete the observation table and quiz.
⭐ Engineering Thinking Challenge

Suppose the input voltage increases from 8 V to 12 V while the Zener is rated at 5.1 V. What should happen to the output voltage, assuming the circuit remains within its proper operating range?

⚠️ Real Laboratory Safety

Important:

A real Zener diode must not be operated above its rated power dissipation. The series resistor must be selected to limit current. Excessive Zener current can permanently damage the device.