ELE 632 Lecture 4: BME 63. March 16,2017

Implement the following multiple output combinational logic circuit using a 4 line to

16-line decoder: F1= ∑m (0, 1, 4, 7, 12, 14, 15) F3= ∑m (2, 3, 7, 8, 10)

 F2= ∑m (1, 3, 6, 9, 12) F4= ∑m (1, 3, 5)

Find y as a function of t if

y(0)=9,y′(0)=6.

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.