Explain bourdon tube pressure sensing principle and identify the typical output signal type for a differential pressure transmitter.

• A. A bourdon tube deforms with pressure; movement is converted to output; DP transmitters typically provide 4-20 mA or digital signals.
• B. A bourdon tube amplifies pressure; DP output is only voltage.
• C. The mechanism is optical; DP output is a radio signal.
• D. It uses ultrasonic reflection; DP output is mechanical.

Answer: (A)