Zener diode when used as a voltage regulator is connected a) in forward bias b) in reverse bias c) in parallel to the load d) in series with the load

Options

A. a and b are correct
B. b and c are correct
C. a is only correct
D. d is only correct

Answer

To solve the question regarding the connection of a Zener diode when used as a voltage regulator, we will analyze the options step by step.

### Step 1: Understanding Zener Diode Operation
A Zener diode is designed to allow current to flow in the reverse direction when a specific reverse voltage, known as the Zener breakdown voltage, is reached. In this breakdown region, the Zener diode can maintain a constant voltage across it.

**Hint:** Recall that Zener diodes are specifically designed to operate in reverse bias to regulate voltage.

### Step 2: Evaluating Forward Bias
When a Zener diode is connected in forward bias, it behaves like a regular diode. This means it will conduct current only when the forward voltage exceeds a certain threshold (approximately 0.7V for silicon diodes). This is not suitable for voltage regulation.

**Hint:** Consider the behavior of a standard diode in forward bias and how it differs from a Zener diode in reverse bias.

### Step 3: Evaluating Reverse Bias
In reverse bias, once the reverse voltage exceeds the Zener breakdown voltage, the Zener diode conducts and maintains a constant voltage across itself. This is the principle behind using a Zener diode as a voltage regulator.

**Hint:** Think about how the Zener diode stabilizes voltage in a circuit when connected in reverse bias.

### Step 4: Connection to Load
For voltage regulation, the Zener diode is typically connected in parallel with the load. This way, it can provide a stable voltage to the load while allowing excess current to bypass through the Zener diode when the input voltage exceeds the Zener voltage.

**Hint:** Visualize the circuit configuration where the load is connected to the Zener diode to understand the parallel connection.

### Step 5: Analyzing the Options
Now, let's analyze the options provided:
- a) In forward bias - Incorrect, as it does not regulate voltage.
- b) In reverse bias - Correct, as this allows the Zener diode to operate in its breakdown region.
- c) In parallel to the load - Correct, as this is how it is typically connected for voltage regulation.
- d) In series with the load - Incorrect, as this would not allow for voltage regulation.

### Conclusion
The Zener diode, when used as a voltage regulator, is connected in reverse bias and in parallel to the load. Therefore, the correct answer is both **b) in reverse bias** and **c) in parallel to the load**.

**Final Answer:** The Zener diode when used as a voltage regulator is connected in reverse bias (option b) and in parallel to the load (option c).