Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E7A
E7A01E7A

Which circuit is bistable?

Deep Dive: E7A01

The correct answer is C: A flip-flop. Which circuit is bistable is a flip-flop. Flip-flops have two stable states (bistable). For amateur radio operators, this is important for digital circuits. Understanding this helps when working with digital logic.

Why Other Answers Are Wrong

Option A (AND gate): Incorrect. AND gate isn't bistable - flip-flops are bistable. AND gate isn't bistable. Option B (OR gate): Incorrect. OR gate isn't bistable - flip-flops are bistable. OR gate isn't bistable. Option D (Bipolar amplifier): Incorrect. Bipolar amplifier isn't bistable - flip-flops are bistable. Bipolar amplifier isn't bistable.

Exam Tip

Bistable circuit = flip-flop. Think 'B'istable = 'B'inary 'S'table (two stable states). Flip-flops have two stable states (bistable). Not AND gate, not OR gate, not bipolar amplifier - just flip-flop.

Memory Aid

Bistable circuit = flip-flop. Think 'B'istable = 'F'lip-'F'lop. Flip-flops have two stable states (bistable). Important for digital circuits.

Real-World Example

A bistable circuit: It's a flip-flop. Flip-flops have two stable states (0 and 1) and can remain in either state until changed. This is the circuit - flip-flop is bistable.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E7A

Reference: 2024-2028 Question Pool · E7 - Practical Circuits

Key Concepts

Circuit Bistable Flip-flop

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E7A topic.