Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E6A
E6A06E6A

What is the beta of a bipolar junction transistor?

Deep Dive: E6A06

The correct answer is B: The change in collector current with respect to the change in base current. What is the beta of a bipolar junction transistor is the change in collector current with respect to the change in base current. Beta (β) = ΔIC/ΔIB. For amateur radio operators, this is important for transistor knowledge. Understanding this helps when working with transistors.

Why Other Answers Are Wrong

Option A: Incorrect. Frequency at which current gain reduced to 0.707 isn't beta - beta is current gain. Frequency isn't beta. Option C: Incorrect. Breakdown voltage of base-to-collector junction isn't beta - beta is current gain. Breakdown voltage isn't beta. Option D: Incorrect. Switching speed isn't beta - beta is current gain. Switching speed isn't beta.

Exam Tip

Beta of BJT = change in collector current / change in base current. Think 'B'eta = 'B'ase current controls 'C'ollector current (ΔIC/ΔIB). Beta (β) = ΔIC/ΔIB. Not frequency, not breakdown voltage, not switching speed - just current gain.

Memory Aid

Beta of BJT = change in collector current / change in base current. Think 'B'eta = 'C'urrent gain. Beta (β) = ΔIC/ΔIB. Important for transistor knowledge.

Real-World Example

The beta of a bipolar junction transistor: It's the change in collector current with respect to the change in base current. Beta (β) = ΔIC/ΔIB. This is the current gain of the transistor. This is what beta is - current gain.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E6A

Reference: 2024-2028 Question Pool · E6 - Circuit Components

Key Concepts

Beta Bipolar junction transistor Change in collector current Change in base current

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E6A topic.