Explain the function of a 'pilot-operated check valve' within a hydraulic circuit and provide an example of its application in construction equipment.

A pilot-operated check valve in a hydraulic circuit allows free flow in one direction but blocks flow in the opposite direction unless a pilot pressure is applied. It's essentially a check valve that can be opened by an external signal. A standard check valve allows fluid to flow freely in one direction while preventing flow in the reverse direction. It uses a spring-loaded poppet or ball that seals against a seat. Pressure from the free-flow direction pushes the poppet open, allowing flow. Pressure from the reverse direction forces the poppet against the seat....