Which relay contact configuration is held closed by a spring?

Which relay contact configuration is held closed by a spring?

• A. Normally Closed
• B. Normally Open
• C. Push Button Switch
• D. Solenoids

Answer: (A)

In this case the key idea is how a relay contact is biased when the coil is not energized. A normally closed contact is held closed by a return spring that pushes the movable contact against the fixed contact. When the relay coil is energized, the magnetic force pulls the armature or contact away, breaking the circuit. So the default state, with no power, is closed because the spring keeps it in that position. The other items don’t describe this default bias: a normally open contact is biased open by a spring and closes only when energized, while a push button switch or a solenoid are actuator devices, not the specific contact bias being described.

In this case the key idea is how a relay contact is biased when the coil is not energized. A normally closed contact is held closed by a return spring that pushes the movable contact against the fixed contact. When the relay coil is energized, the magnetic force pulls the armature or contact away, breaking the circuit. So the default state, with no power, is closed because the spring keeps it in that position. The other items don’t describe this default bias: a normally open contact is biased open by a spring and closes only when energized, while a push button switch or a solenoid are actuator devices, not the specific contact bias being described.