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7.5 ECTS
All the students registered in the course AT1TX1Textile Electronics
Ladokcode: AT1TX1 The exam is given to: Name:
Personal number:
Date of exam: 2018-06-01 Time:
9:00 – 13:00
Means of assistance:
The student can use written documentation to do this exam. That includes books, papers, printouts, lecture notes, written notes, etc.
Calculators and dictionaries are allowed including electronic dictionaries Laptop computers are not allowed.
Total amount of point on exam: 45 points
Total amount of questions: 6 questions
Requirements for grading:
The ECTS scale will be used to grade this exam. That means that grades A,B,C,D,E,FX and F, will be used.
To pass the exam requires a grade E given with minimum of 22 points F < 20, FX≥20, E≥22, D≥27, C≥32 B≥36 and A≥40
Additional information:
Please, use a separate sheet of paper for each question. Subquestions, i.e. a, b, c etc can be on the same
sheet of paper
Questions during exam: Emanuel Gunnarson, phone 0707-541811
IMPORTANT! Do not forget to write your name on each paper you hand in.
Good Luck!
Examiner: Phone number:
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1. Electrical Properties
Explain why metals present better conductive properties than other material
(2 Points)
2. Sheet Resistance
a). Explain the reason why a piece of conductive fabric with dimensions 3 cm wide and 3 long has the same resistance than a piece with dimensions 7 cm wide and 7 cm long of the same fabric same fabric
(3 Points) b). Explain how is possible that a single piece of fabric with dimensions: 50 x 25 mm and sheet resistance = 16 Ohms/square, can have both a total resistance of 32 Ohms and 8 Ohms.
(3 Points)
3. Electrical Circuits
We know that current occurs when free electrons move in the presence of an gradient of potential. In an electrical circuit, what are the two conditions required to have electrical current flowing the circuit elements?
(2 Points)
4. Circuit Transformation and Impedance
Transform the following parallel and series connections into a single impedance a) find the value of the
resistor between A and B
b) find the value of the capacitor between A and B
c) find the value of the impedance between A and B at frequency 15 kHz
(3 points) (3 points) (4 points)
*Note ω = 2 π f
5. Circuit Analysis
Find out the current flowing through each of the passive elements and voltage at each
node. (10 points) A B 10 Ω 10 Ω 10 Ω 1000 Ω A B 10 uF 10 uF 10 nF A B 100 nF 100 nF 50 Ω A 50 Ω 50 Ω 100pF 1000 Ω 10 V
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6. Operational Amplifier
a) find out the gain of the op-amp circuit in the following circuit.
(10 Points) Note: the Gain should be given in function of Rf and Rg
b) IF Rg = 1kOhm and Rf= 5 kOhm, what is the minimum value for Vcc to avoid saturation at the output of the Op-Amp if Vin= 3 Volts.
(5 Points)
