In typical transistor operation, base current constitutes approximately_________ of the total emitter current?
Show answer Hide answer
Answer: D. 5%
Explanation
The base region of a bipolar transistor is manufactured to be extremely thin and lightly doped with impurities. Because of this physical design, only a tiny fraction of the injected charge carriers recombines within the base. Consequently, the resulting base current constitutes approximately five percent of the total emitter current flow. Bipolar junction transistors rely on minority carrier injection from the heavily doped emitter into the base. The vast majority of injected carriers travel straight through the narrow base region into the collector. The tiny percentage that recombines makes up the measurable base current required for transistor operation.
A base current of 25 percent would indicate extremely poor transistor construction and very low current gain. Twenty percent is far too high for standard bipolar transistors used in modern electronic circuit designs. Stating 35 percent contradicts the fundamental semiconductor physics principles governing modern junction transistors.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. A rheostat differs from a potentiometer in the sense that it_____________?
Show answer Hide answer
Answer: B. has higher wattage rating
A rheostat is typically designed with a higher wattage rating than a potentiometer because it controls current directly. Handling large electrical currents requires thicker resistive elements capable of dissipating subst...
Q2. Which type of machinery experiences heavy load fluctuations ?
Show answer Hide answer
Answer: A. Printing machine
Printing machines experience continuous and heavy load fluctuations during high speed paper feeding and printing. Variable torque demands require printing presses to utilize robust mechanical drives and motor controls. S...
Q3. Which of the following can serve as an indicator of electric intensity ?
Show answer Hide answer
Answer: B. V/A
Electric intensity, or electric field strength, measures potential difference distributed across a specific distance interval. Potential measured in volts divided by distance represented dimensionally matches the intensi...
Q4. When selecting an electric motor to drive a flour mill, which electrical specification is of minimal relevance ?
Show answer Hide answer
Answer: D. Braking
Flour mills require constant running and high starting torque for heavy milling machinery. Electric braking is generally unnecessary for their standard continuous grinding operation. Motors operate steadily without needi...
Q5. Given a 21 V source applied to a circuit where R1 = 5 ohms, R2 = 35 ohms, and R3 = 14 ohms, with R1 in series with the parallel pair R2 and R3, what is the current through R2?
Show answer Hide answer
Answer: B. 400 mA
Calculating the parallel resistance of thirty-five and fourteen ohms yields exactly ten ohms of equivalent resistance. Adding the series resistor of five ohms gives a total circuit resistance of fifteen ohms altogether....
Q6. Which device operates on the principle of magnetic torque exerted on a current-carrying conductor in a magnetic field ?
Show answer Hide answer
Answer: D. all of the above
Galvanometers, ammeters, and voltmeters all operate based on magnetic torque exerted on current-carrying conductors inside a magnetic field. When electric current flows through a movable coil positioned within a permanen...