Staging & Prognostic Factors Flashcards
7 cards from real CET practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Staging & Prognostic Factors flashcards as text
A power supply uses a pre-regulator stage followed by a linear regulator stage. What is the primary benefit of this two-stage approach?
Answer: Reduces power dissipation in the linear regulator by lowering its input-output differential
The pre-regulator brings the voltage close to the desired output, minimizing the headroom across the linear stage and reducing its heat dissipation.
In a staged RF receiver (antenna → LNA → mixer → IF amplifier), which stage primarily determines selectivity?
Answer: IF amplifier with bandpass filter
The IF amplifier stage, combined with a narrow bandpass filter at a fixed intermediate frequency, provides the primary channel selectivity in a superheterodyne receiver.
Temperature coefficient (TC) of a resistor is a prognostic factor because it indicates:
Answer: How much the resistance value drifts with temperature changes
TC specifies the rate of resistance change per degree Celsius, which is critical for predicting circuit performance across operating temperature ranges.
Burn-in testing of electronic assemblies is performed to eliminate failures from which reliability phase?
Answer: Infant mortality phase
Burn-in screens out early-life failures caused by manufacturing defects, ensuring that shipped units are past the infant mortality region of the bathtub curve.
In a staged filter design (pre-filter → main filter → post-filter), each stage is typically designed so that:
Answer: Each stage handles progressively finer rejection or different frequency bands
Staged filtering distributes the rejection task, with early stages removing large interferers and later stages achieving finer selectivity with reduced signal degradation.
Which component characteristic is the most important prognostic factor when evaluating electrolytic capacitors for long-term reliability?
Answer: Equivalent Series Resistance (ESR) trending upward over time
Increasing ESR in electrolytic capacitors indicates electrolyte drying and degradation, which leads to reduced performance and eventual failure.
In a phased-array system, 'staging' the transmit power amplifiers in multiple lower-power stages rather than one high-power stage primarily improves:
Answer: Reliability through redundancy and reduced per-stage thermal stress
Distributing amplification across multiple stages reduces thermal stress per unit, improves reliability, and allows graceful degradation if one stage fails.