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The operating point of a transistor known as _______.
active point
quiescent point
cut-off point
threshold point
quiescent point
The operating point of a transistor is referred to as the quiescent point or Q-point. It represents the fixed DC voltage and current values (VCEQтАЛ,ICQтАЛ) at which the transistor operates when no input signal is applied.
The operating point of a transistor is referred to as the quiescent point or Q-point. It represents the fixed DC voltage and current values (VCEQтАЛ,ICQтАЛ) at which the transistor operates when no input signal is applied.
VCEQтАЛ=VCCтАЛтИТICQтАЛRCтАЛ тАФ DC load line equation
ICQтАЛ=╬▓IBQтАЛ тАФ Relation between collector and base current at the operating point
The Q-point is determined by the intersection of the DC load line, governed by Kirchhoff's Voltage Law (VCCтАЛ=ICтАЛRCтАЛ+VCEтАЛ), and the output characteristic curves of the transistor. By setting the biasing resistors properly, the Q-point is usually placed at the center of the active region to allow maximum symmetrical swing for AC signals without clipping.
Q-point stands for Quiescent point, implying a 'quiet' or steady-state condition.
A well-stabilized Q-point is essential to prevent thermal runaway and signal distortion.
The location of the Q-point dictates the region of operation: active, saturation, or cut-off.
Temperature variation can shift the Q-point, necessitating bias compensation circuits.
Ensures predictable transistor behavior for amplifier designs
Allows for linear amplification of input signals
Susceptible to thermal instability if not biased correctly
Requires additional components for stabilization
Small signal amplifiers
Power amplifiers
Active filters
The term 'quiescent' means dormant or steady, describing the DC condition before an AC signal is injected.
Option A (Active point) is a general descriptor of a region, not the specific name of the DC operating point.
Option C (Cut-off point) represents the state where the transistor acts as an open switch (ICтАЛтЙИ0).
Option D (Threshold point) is typically associated with MOSFET conduction (VGSтАЛ>VthтАЛ), not BJT operating points.
B is correct тАФ The operating point of a transistor is technically defined as the quiescent point (Q-point).
Always remember that the Q-point must lie within the active region for linear amplifier operation; if it shifts into the cut-off or saturation regions, severe signal distortion occurs.
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