Which statement best describes an active instrument transmitter?

Which statement best describes an active instrument transmitter?

• A. Active transmitters draw power from the loop and have no local power source.
• B. Active transmitters supply their own power and may provide higher-level output.
• C. Active transmitters only operate at 4 mA.
• D. Active transmitters are passive devices.

Answer: (B)

Active transmitters have their own local power source, which lets them generate or amplify the signal and often deliver higher-level outputs than the loop alone can provide. Because they’re powered independently, they’re not limited by the energy available from the current loop and can drive different output types or handle longer runs and larger loads without losing signal integrity. That’s why the statement that they supply their own power and may provide higher-level output is the best description. The other ideas describe loop-powered or passive devices: drawing power from the loop means no local power source, which isn’t true for an active transmitter; claiming they only operate at 4 mA is incorrect since active transmitters can provide various output levels, including voltages or different current ranges; and calling them passive is the opposite of what “active” signifies.

Active transmitters have their own local power source, which lets them generate or amplify the signal and often deliver higher-level outputs than the loop alone can provide. Because they’re powered independently, they’re not limited by the energy available from the current loop and can drive different output types or handle longer runs and larger loads without losing signal integrity. That’s why the statement that they supply their own power and may provide higher-level output is the best description.

The other ideas describe loop-powered or passive devices: drawing power from the loop means no local power source, which isn’t true for an active transmitter; claiming they only operate at 4 mA is incorrect since active transmitters can provide various output levels, including voltages or different current ranges; and calling them passive is the opposite of what “active” signifies.