Which term specifies a circuit that maintains current flow after the initiating momentary switch is released?

• A. Seal-in circuit
• B. OTL
• C. Status
• D. Transducer

Answer: (A)

A seal-in circuit is designed to keep current flowing after the initiating momentary switch is released. It achieves this by using a normally open auxiliary contact of the control relay wired in parallel with the start pushbutton. When you press the start button, the relay energizes and its own contact closes, creating a path that bypasses the button. That closed path allows the coil to stay energized even after the momentary switch is released. A stop switch in series can interrupt this path to de-energize the circuit when needed. This self-holding or latching behavior is what the term seal-in circuit describes. Transducers and status indicators aren’t about maintaining current, and OTL refers to a different kind of latch behavior related to outputs, not the holding path itself.