What does a flip-flop do in digital circuits?

A flip-flop in digital circuits functions primarily as a memory element that stores a single bit of data. It is a bistable device, meaning it has two stable states which represent the binary values 0 and 1. When the input is applied (via a clock signal or other triggering means), the flip-flop can change its outputs, effectively allowing it to hold or "flip" its state depending on the information it receives.

This ability to maintain a state makes flip-flops fundamental building blocks in memory devices, registers, and even in sequential logic circuits where timing and data storage are critical. Each flip-flop can thus be used to store one bit, and multiple flip-flops can be combined to store larger binary numbers or implement more complex functionality.

In this context, the other options do not accurately define the primary role of a flip-flop. While transmitting signals or converting them are functions associated with other digital components (like buffers or transceivers), and arithmetic calculations are typically performed by adders or other computational units, the core identity of a flip-flop lies in its ability to store data, which is why storing a single bit of data is the correct answer.