assignment and cat2

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KENYATTA UNIVERSITY

EEE 414 Instrumentation

CAT 2 and ASSIGNMENT

1. A thermocouple circuit uses a chromel-alumel thermocouple which gives an e.m.f. of 33.3mV when

measuring a temperature of 8000C with reference temperature of 0

0C. The resistance of the meter coil,

Rm is 50 and a current of 0.1mA gives full scale deflection. The resistance of junction and leads, Re

is 12. Calculate:

i. Resistance of the series resistance if a temperature of 8000C is to give full scale deflection.

ii. The approximate error due to a rise in 100C in the copper coil of the meter, given the

resistance temperature co-efficient of the coil is 0.00426/0C.

2. A Barium Titanate pickup has the dimensions of 4mm by 4.5mm by 1.0mm. the force acting on its is

10N. The charge sensitivity of Barium Titanite is 145/ and its permittivity is 12.5/. If the

modulus of elasticity of barium titanite is 12 106/2. Calculate the strain, charge and capacitance

of the crystal.

3. A 42 cm length of 2.3 mm thick copper-invar bimetallic strip is wound into a spiral with a radius of

5.2 cm at 68 oF. Determine the deflection of the strip at 70

oC? Take coefficients of linear expansion

for copper and invar to be 9.4 x 10-6

and 0.67 x 10-6

respectively

4. For the multirange digital ammeter circuit diagram shown below, determine the values of the shunt

resistors so that the multirange ammeter measures current in the given that the output voltage is 5 V.

following ranges:0 to 10 mA, 0 to 1 mA, 0 to 100 A and 0 to 10 A

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5. A 0 to 200 V voltmeter has a guaranteed accuracy of 1% of the full scale reading. The voltmeter is

used to measure voltages of 40 V and 80 V. Calculate the limiting error in % in each case and

comment upon the results

6. The resistor 1 and 2 are connected in parallel. The value of the resistance are 1 = 100

0.1 and 2 = 50 0.03 . Determine the uncertainty in the combined resistance

Instructions:

i. The deadline for submitting is 30th March 2015

ii. They will be considered for CONTINUOUS ASSESSMENT as well as ASSIGNMENT

iii. To be done in Groups of not more than 5 people

iv. To be submitted online to roysam.ku@gmail.com