HOW I DO MY WORK WITH AIQ AND MOVIE
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A dipole antenna dimensions has been designed to operate in 65MHz.
Will the same antenna work properly if frequencies a) 130MHz b) 195MHz are used?
Your answer should include the current distribution and impedance variation along the length of the antenna and how those are affected when frequencies of 130MHz and 195MHz are introduced. Also, include sketches of radiation patterns with respect to the changes in frequencies used.
Make sure you give descriptive answer in order to achieve full marks. Use diagrams to help you with the answer.
Question 3 (IEIIQ16)
A 3 W rated Zener diode is used in a shunt voltage regulator circuit to supply a dc output of 12 V to a variable load with a minimum resistance of 240 Ω. The supply voltage varies between 20 V and 24 V.
3.1 Draw the circuit diagram.
3.2 Calculate the range of series resistance that may safely be used in this circuit. Select a single suitable standard value.
3.3 Calculate the maximum power rating required for the series resistor.
Question 4 (IEIIQ17)
A simple Zener voltage regulator is required to provide a steady regulated output voltage of 10 V under a maximum load of 80 mA, while the input voltage to the regulator varies between 12 V and 14 V.
17.1 Calculate the maximum rated current value of a Zener diode to be used
17.2 Calculate the minimum power for the Zener that could be used safely.
17.3 If a 5 W rated Zener were to be used in this circuit:
(i) Calculate the maximum rated current value of a Zener device to be used
(ii) Calculate the range of possible RS. limiting resistor values.
(iii) Suggest a suitable standard E12 resistor value