Question
What is a characteristic of a grounded-grid amplifier?
Answer Options
- A) High power gain
- B) Low input impedance
- C) High electrostatic damage protection
- D) Low bandwidth
Correct Answer: B
Explanation
A grounded-grid (or common-grid) configuration for a vacuum tube or a common-base configuration for a transistor is a non-inverting amplifier topology known for stability and robust operation. Unlike the common-cathode or common-emitter circuits, the input signal is applied to the cathode (or emitter) terminal, which presents a unique impedance characteristic.
Because the input signal must drive current directly into the highly conductive cathode/emitter, the key characteristic of a grounded-grid amplifier is low input impedance (typically 50 to a few hundred ohms). This makes it easy to couple to standard 50-ohm transmission lines without complex matching networks, which simplifies design, although the voltage gain is generally lower than other topologies.
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