Question

Which of the following is true with respect to the passive optical sensor?

(a) Not affected by EMI

(b) Does not require an electrical supply

(c) Output from the sensor is an optical signal

(d) Processing this signal does not require any electrical device

This question was addressed to me in quiz.

I'd like to ask this question from Digital Implementation topic in division Fly by Wire Flight Control of Avionics

Answer 1

The correct choice is (d) Processing this signal does not require any electrical device

Easiest explanation: Passive optical sensors offers particular advantages as these sensors are not affected by EMI. Passive optical sensors are defined as sensors which do not require electrical supplies or any electronic processing at the sensor, the output of the sensor being an optical signal which is modulated by the quantity being measured. The processing of this optical signal is carried out by a separate electronic unit which is fully screened from EMI, the only connection between the sensor and the electronic unit being an optical fibre cable.