The bistable turns on to actuate an alarm at a temperature of 130°F. The bistable has a 5°F deadband, or neutral zone ___

Refer to the drawing of a temperature alarm circuit (see figure below).

Pressure Alarm Circuit -50

The orientation of the bistable symbol indicates the characteristics of the bistable, as is normal for a control circuit diagram.

The bistable turns on to actuate an alarm at a temperature of 130°F. The bistable has a 5°F deadband, or neutral zone.

If the current temperature is 150°F, which one of the following describes the alarm circuit response as temperature slowly decreases to 110°F?

A. The alarm is currently actuated and will not turn off.
B. The alarm will actuate at 130°F and will not turn off.
C. The alarm is currently actuated and will turn off at 125°F.
D. The alarm will actuate at 130°F and will turn off at 125°F.

Show Answer

Answer: B

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