Question

Why output of transducer is not directly connected to indicator or display?

(a) Low level output is produced

(b) High level output is produced

(c) No output is produced

(d) Input is fed directly

The question was posed to me at a job interview.

Question is from Instrumentation Amplifier topic in chapter Operational Amplifier Applications of Linear Integrated Circuits

Answer 1

The correct answer is:

(a) Low-level output is produced

Explanation:

The output of a transducer is typically a low-level signal that cannot directly drive an indicator or display. This is because:

1. Low Signal Strength: Transducers produce small voltage or current outputs, often in the millivolt or microvolt range, which are insufficient for proper operation of most indicators or displays.
2. Signal Conditioning Needed: The transducer's output needs to be amplified and conditioned (e.g., filtered or converted) before it can be used to drive a display or indicator.
3. Impedance Mismatch: Directly connecting a transducer to an indicator may lead to signal distortion or loss due to impedance mismatches.

This is why an instrumentation amplifier or other signal processing circuit is typically used between the transducer and the display device to boost the signal strength and ensure compatibility.