When used in a circuit, a Zener diode is always
(a) at a temperature below 0 °C
(b) connected in series
(c) reverse-biased
(d) forward-biased
(e) None of the above.
Answer (2)
Zener diodes are designed to operate in the breakdown region.
They are reverse-biased to operate in this region.
Zener diodes are used to regulate voltage in circuits.
Therefore, a zener diode is always reverse-biased. re v erse − bia se d
Explanation
Understanding Zener Diodes A zener diode is a special type of diode designed to reliably allow current to flow 'backwards' when a certain set reverse voltage is reached. This is known as the zener voltage or breakdown voltage. Zener diodes are used to regulate voltage in a circuit.
Operating in Breakdown Region Zener diodes are designed to operate in the breakdown region. This means they are intended to be reverse-biased. When the reverse voltage across the zener diode reaches the zener voltage, the diode starts conducting in the reverse direction, maintaining a nearly constant voltage across it.
Circuit Configuration Considering the typical circuit configuration for a zener diode to regulate voltage, it is connected in parallel with the load and is reverse-biased. This allows it to maintain a stable voltage across the load when the input voltage fluctuates.
Conclusion Based on the above analysis, the correct option is that a zener diode is always reverse-biased when used in a circuit.
Examples
Zener diodes are commonly used in voltage regulators to maintain a stable output voltage despite variations in the input voltage or load current. For example, in a 5V power supply, a zener diode with a zener voltage of 5.1V can be used to ensure that the output voltage remains close to 5V, protecting sensitive electronic components from voltage spikes or fluctuations. This ensures the reliable operation of devices like microcontrollers and sensors.
A Zener diode is always reverse-biased when used in a circuit, which allows it to operate in the breakdown region. This characteristic is essential for its function in voltage regulation. Therefore, the correct answer is option (c): reverse-biased.
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