I have attached a file which has a question to be solved.
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Question 1
A simple Zener diode shunt voltage regulator is to supply 12 V to a load which normally draws a load current which varies from 0 to 50 mA. The input voltage varies between 15 V and 18 V.
1.1 Calculate the maximum rated current value of a Zener device to be used.
1.2 Calculate the minimum power for the Zener that could be used safely.
1.3 If a 5 W rated Zener were to be used, calculate the range of possible RS. values and hence suggest a suitable standard E12 resistor value.
1.4 State four (4) conditions under which a Zener diode dissipates minimum power in a regulator circuit.
Question 2 (IEIIQ15)
A 2.5 W Zener diode is used in a simple Zener shunt voltage-regulator to supply 5.1 V to a load which normally draws a load current varying from 0 to 125 mA. The input voltage varies between 8 V and 9.5 V
2.1 Give two (2) reasons for the inclusion of the series resistor in the Zener-regulator circuit.
2.2 Calculate the range of series resistance that may safely be used in this circuit.
2.3 Select a single suitable standard E12 resistor value and give its colour code with 1 % tolerance.
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
Question 5 (IEIIQ18)
A simple Zener shunt voltage regulator is to supply a 10 V to load of 100 mA, the input supply voltage varies between 15 V and 20 V.
5.1 Draw the circuit diagram.
5.2 Calculate the minimum power for the Zener that could be used safely in this circuit.
5.3 Using a Zener diode with a power rating of twice this minimum value.
5.4 Calculate the range of series resistance that may safely be used in this circuit and suggested a suitable standard resistance value.
Question 6 (IEIIQ19)
A voltage regulator is required to provide a regulated terminal voltage of 25 V at a maximum load of 150 mA. The input volage varies between 50 V and 75 V dc.
6.1 Calculate the minimum power for the Zener that could be used safely in this circuit.
6.2 If a 30 W rated Zener is used, calculate the range of possible series resistance, RS. values and suggest a suitable standard E12 resistor value.
