## calculate the power incident on the detector and the detector output current.

An optical fibre transmission system consists of a circular LED source, a 2-metre length of optical fibre and a circular PIN diode detector. Both the source and detector are positioned 100 µm from the ends of the fibre. Detailed data for the source, a glass fibre, a polymer fibre and the detector are given below. Use this data to perform the following calculations.

(a) The total power Ps emitted by the source in all directions (use eqn [15.23b]).

(b) The numerical aperture and maximum angle of acceptance of the glass fibre.

(c) The numerical aperture and maximum angle of acceptance of the polymer fibre.

(d) The source and detector are linked by the glass fibre; calculate the power input to the fibre, the fibre transmission factor, and power output from the fibre.

(e) The source and detector are now linked by the polymer fibre; calculate the power input to the fibre, the fibre transmission factor, and power output from the fibre.

(f) For both the glass system of (d) and the polymer system of (e), calculate the power incident on the detector and the detector output current.

### Calculate the maximum achievable bridge out-of-balance voltage for an applied torque T of 103 N m given the following

Four strain gauges, with specification given below, are available to measure the torque on a cylindrical shaft 4 cm in diameter connecting a motor and load. (a) Draw clearly labelled….

### Find the gain and phase characteristics of the maintaining amplifier.

A solid-state capacitive humidity sensor has a capacitance given by: C = 1.7 RH + 365pF where RH is the percentage relative humidity. The sensor has an associated parallel resistance….

### calculate the mean velocity of the gas at maximum flow rate

A pitot tube is used to measure the mean velocity of high pressure gas in a 0.15 m diameter pipe. At maximum flow rate the mean pitot differential pressure is….