ECET210 WEEK 7 HOMEWORK PART 2

This is a Regulated DC Power Supply design problem. The students must choose the values of the following parameters for the design:

a) VOut = 6.0 V or 10.0 V or 12.0 V

b) RL = ?? Ω and R1 = ?? Ω

c) Wattage ratings of R1 and RL to be determined

d) IL = 20 mA; IZD = 20 mA; IR1 = ?? mA

e) Voltage VA_DC = VB + 3 V

f) Turns ratio, n = ??

i) Pick an output voltage number from (a)

ii) Choose the appropriate Zener Diode from the data sheet given below.

iii) Determine the Ω values and the wattage ratings of R1 and RL.

iv) Determine the peak value of the transformer secondary voltage VS.

v) Determine the transformer turns ratio n.

Assume the following:

a) Rectifier diode drop = 0.7 V for each. The DC Voltage (after smoothing by the capacitor) is equal to the peak value of the peak value of the full wave rectified pulses.

b) The Zener voltages are the Nominal Values

AC

V

in_RMS

= 120 V

f

In

= 100 Hz

V

S

D1

D2

D4D3C

Z

D

1N4001

1N4001

1N4001

1N4001

R

L

, Ω

R

1

Ω

V

A

V

Out

A

B

I

R1

I

L

I

ZD

3300 µF

Bridge Rectifier

Capacitor Filter & Zener Diode Regulator

Step Down

Power Transformer

n

AC

n

Vin_RMS = 120 V fIn = 100 Hz

VS

D1

D2

D4

D3

C

ZD

1N4001

1N4001

1N4001

1N4001

RL, Ω

R1 Ω

VA

VOut

A

B

IR1

IL

IZD

3300 µF

Bridge Rectifier

Capacitor Filter & Zener Diode Regulator

Step Down Power Transformer