## 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 of 100 kΩ. The sensor is incorporated into a feedback oscillator system with a pure inductance and a maintaining amplifier. The oscillator is to give a sinusoidal output voltage at the natural frequency of the L–C circuit for a relative humidity between 5 and 100%.

(a) Draw a diagram of a suitable oscillator system.

(b) If the frequency of the output signal is to be 100 kHz at RH = 100%, calculate the required inductance.

(c) Find the gain and phase characteristics of the maintaining amplifier.

### 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….

### 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….

### Calculate an accurate value for the differential pressure developed across the chosen Venturi, at maximum flow rate.

A Venturi is to be used to measure the flow rate of water in a pipe of diameter D = 0.20 m. The maximum flow rate of water is 1.5….