To achieve good bias stabilization in a voltage-divider bias network, the current I1 passing through R1 and R2 should be set equal to or greater than_____________?
Show answer Hide answer
Answer: A. 10 IB
Explanation
Setting the divider current equal to or greater than ten times base current ensures stability. This high bleeder current makes fluctuations in transistor base current negligible to divider voltages. Consequently, the operating bias point remains stable despite variations in transistor current gain. Voltage-divider bias provides a stable operating point for bipolar junction transistors using resistors. Base current represents the small control current entering the base terminal of the transistor. Good bias stabilization prevents temperature changes from shifting the quiescent operating point of amplifiers.
Reliable bias stabilization is essential for preventing thermal runaway in power amplifier circuits. Electronic hardware designers follow the ten-percent rule or ten-times rule as a standard design guideline. Properly stabilized circuits operate reliably across wide ambient operating temperature ranges. Option B is incorrect because a factor of three provides insufficient immunity to base current changes. Option C is incorrect because a factor of two allows transistor parameters to disrupt bias stability. Option D is incorrect because a factor of four still risks thermal instability in sensitive circuits.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. Which mechanical locomotive or engine designs exhibit the maximum unbalanced inertial forces_______________?
Show answer Hide answer
Answer: B. Steam locomotives
Steam locomotives feature heavy reciprocating pistons, connecting rods, and massive mechanical driving wheels. The linear reciprocating motion of pistons creates large unbalanced inertial forces during high-speed travel....
Q2. To ensure proper signal amplification in a transistor stage, where should the Q-point be positioned along the DC load line_____________?
Show answer Hide answer
Answer: B. Middle
Centering the Q point establishes equal voltage and current margins in both directions. This balanced operating position allows maximum symmetrical signal swing without waveform clipping. Placing the quiescent point else...
Q3. Increasing the reverse bias voltage applied to a JFET gate causes the width of the conducting channel to ______________?
Show answer Hide answer
Answer: A. is decreased
Increasing the reverse bias voltage applied to the gate widens the depletion region. This expanding depletion layer encroaches further into the conductive semiconductor channel region. Consequently, the physical cross-se...
Q4. Under what condition is an Ajax-Wyatt induction furnace initially started____________?
Show answer Hide answer
Answer: B. it is filled above core level
An Ajax-Wyatt core-type induction furnace relies on molten metal to form the secondary circuit loop. Starting the furnace with metal filled below the core level breaks this critical electrical circuit. Therefore, operato...
Q5. For high-temperature radiant heating around 2250°C, what materials are used to construct the heating elements____________?
Show answer Hide answer
Answer: C. tungsten alloy
Tungsten alloys possess exceptionally high melting points and structural strength at high heats. These metallurgical properties prevent structural failure during extreme high temperature operations. Heating elements made...
Q6. For the efficient transfer of thermal energy from one body to another__________?
Show answer Hide answer
Answer: A. temperature of the two bodies must be different
Net thermal energy transfer occurs exclusively when a temperature difference exists between two bodies. Thermodynamic laws dictate that heat flows spontaneously from higher temperature regions to lower ones. Thermal equi...