Which power tool must have a constant pressure switch that automatically shuts off when the pressure is released?

The correct answer is that the power tool which must have a constant pressure switch that automatically shuts off when the pressure is released is indeed the circular saw. This safety feature is crucial for tools like circular saws, where maintaining control and preventing accidental operation is essential for user safety. The constant pressure switch ensures that the saw will only operate while actively being held and controlled by the user, which minimizes the risk of injury if the tool slips or if the user loses grip on the handle.

In contrast, tools such as drill presses, angle grinders, and table saws generally operate differently. Drill presses are typically stationary and can be controlled in a different manner that does not necessitate a constant pressure switch. Angle grinders, while also handheld, are designed to operate continuously until intentionally turned off, allowing for more control in specific applications. Lastly, table saws are generally equipped with other safety features, like blade guards and riving knives, but do not rely on a constant pressure switch since the operator is usually not in direct contact with the blade during operation. Each tool has its own operational needs and safety considerations, making the circular saw unique in requiring the specific switch type noted in the question.