Which circuit is specifically designed to maintain current flow after a momentary activation to keep a circuit energized?

• A. Seal-in circuit
• B. Latch
• C. Interlox
• D. Status

Answer: (A)

Seal-in circuits are designed to keep a circuit energized after a brief activation by creating a self-holding path. When you momentarily push the start (or activation) touch, the relay coil energizes. The relay’s own normally open contact, wired in parallel with the start button, closes and provides a path that keeps the coil energized even after the start button is released. A separate stop (normally closed) contact can break that path to reset the circuit when needed. This holding behavior is why this arrangement is called a seal-in circuit—it “seals in” the energized state until a reset occurs. The other terms don’t describe this specific holding mechanism: a latch is a broader memory concept, while Interlox and Status refer to different functions or devices and don’t capture the self-holding control path.