A common-source JFET amplifier features RD = 820 Ω, a load resistance of 10 kΩ, gm = 5 mS, and Vin = 500 mV. The output signal voltage is__________________?
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Answer: D. 1.89 V
Explanation
The output signal voltage is determined using transconductance multiplied by the parallel load resistance. Parallel combination of drain resistor and load resistance yields the total effective alternating current resistance. Multiplying 5 millisiemens by the parallel resistance value gives the exact output signal voltage. Transconductance relates the change in drain current to a change in gate-source voltage. Common-source amplifiers invert the input signal while providing substantial voltage gain to the circuit. Parallel resistance calculations determine the total ac load seen by the transistor drain terminal.
Calculating signal voltages accurately ensures that audio and radio frequency amplifier stages do not clip. Engineers perform these calculations during the design phase of analog amplification systems. Proper signal level estimation prevents distortion and guarantees optimal dynamic range in electronic equipment. Option A represents an incorrect calculation resulting from improper handling of parallel resistance values. Option B is wrong because it overestimates the expected output voltage by an incorrect decimal factor. Option C incorrectly matches the input signal voltage instead of calculating the amplified output.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
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