How does the breakdown voltage threshold for Zener mechanism change as the junction temperature increases_______________?
Show answer Hide answer
Answer: B. Is decreased
Explanation
The true Zener breakdown mechanism possesses a negative temperature coefficient where breakdown voltage drops as temperature rises. As thermal energy increases inside the semiconductor crystal lattice, fewer electric field lines are needed to induce tunneling. Consequently, the reverse breakdown voltage threshold decreases when the junction operating temperature goes up. Temperature coefficients describe how semiconductor device parameters change in response to fluctuations in operating temperature. Zener breakdown relies on quantum mechanical electron tunneling across a narrow P-N junction depletion region. Semiconductor conductivity generally increases with temperature due to thermally generated electron hole pairs in the lattice.
Stating that the breakdown voltage increases is incorrect and actually describes the behavior of avalanche breakdown mechanisms. Saying it remains the same ignores the well established thermal dependency of semiconductor junction physics. Option D is incorrect because the Zener breakdown threshold explicitly decreases as the junction temperature rises.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. How is the output voltage of an unregulated power supply affected when the load current rises_____________?
Show answer Hide answer
Answer: B. Decreases
As load current increases, internal resistance and transformer impedance cause larger internal voltage drops. These internal voltage losses subtract from the generated voltage, causing the DC output voltage to decrease....
Q2. What happens to the Zener current if the external load resistance decreases in a Zener regulator______________?
Show answer Hide answer
Answer: A. Decreases
When external load resistance decreases, load current increases, leaving less current for the Zener diode and thereby decreasing the Zener current.
Q3. Two identical 15 V Zener diodes are connected in series across a 45 V DC input within a regulated supply. Given a 300 mA max current rating for each, what should the series resistor value be?
Show answer Hide answer
Answer: B. 50 O
Two 15 volt Zener diodes in series drop a combined total of 30 volts across their terminals. Subtracting this 30 volt diode drop from the 45 volt DC input leaves 15 volts across the series dropping resistor. Using Ohm la...
Q4. By what alternative terminology is a Zener diode known ______________diode?
Show answer Hide answer
Answer: A. Breakdown
Zener diodes are designed specifically to operate in their reverse electrical breakdown region without sustaining permanent damage. Because their primary operational characteristic involves controlled reverse breakdown,...
Q5. A power supply exhibiting a voltage regulation of ____________ is classified as unregulated.
Show answer Hide answer
Answer: C. 10 %
A power supply with a voltage regulation figure around ten percent is traditionally classified as unregulated. Tighter regulation figures near zero percent are characteristic of actively stabilized power supplies. Ten pe...
Q6. Which description most accurately portrays a Zener diode?
Show answer Hide answer
Answer: C. It is a constant-voltage device
When operating in its reverse breakdown region, a Zener diode maintains an almost constant voltage across its terminals. Even when the current passing through the diode changes significantly, the terminal voltage remains...