The George Washington University
School of Engineering and Applied Science
Department of Electrical and Computer Engineering
ECE 20 - LAB
Experiment # 3a

Solid-State Diodes
Applications II




Equipment:
You must make up a complete equipment list and have your instructor review it before you start.
 

Components:

·              4 - 1N4002 Diodes

·              1 - 1N751A Zener Diode

·              1 - 7805 Voltage Regulator

·              1 - 12 V CT (center-tapped) Transformer

·              1 - filter capacitor, to be determined by your filter design

·              1 - LED

·              Resistors
 

Objectives:

·              To design, build and test a Zener regulator circuit

·              To design, build and test a 5 VDC regulated power supply

·              To design a filter

·              To design using power ratings

·              To measure ripple voltage and obtain the ripple factor


 

CAUTION!
BE CAREFUL DURING THIS EXPERIMENT!
HAZARDOUS VOLTAGES WILL
BE PRESENT WHEN YOU PERFORM
YOUR MEASUREMENTS!

 

1.- Zener Regulator Design

a.          (HW) Design Zener regulator circuit that has the specifications below. Draw and label the schematic of this circuit Figure #1 - 5.1 V Zener Regulator Circuit. Compute the output voltage corresponding to V S MIN and to V S MAX.
 

b.         (HW) Assemble your design in part a).
 

c.          Verify the correct operation of your design in part a). Take enough readings to prove this. Write down the values for the input and output voltage on Table # 1.
 

d.         Compute the load regulation value.

·              Input: 8.13 VDC + 1.87 VDC

·              Output (unloaded): 5.1 VDC + 5 %

·              Output (loaded): 5.1 VDC + 5 %

·              Type of Load: resistive, 300 Ohms


 
 

2.-  5 VDC Regulator Design With Input Filter & Power On Indicator

a.          (HW) Design a 5 VDC regulated power supply that has the specifications below. Draw and label the schematic Figure # 2 - 5 VDC regulated power supply.
 

b.         Build your design in part a).
 

c.          Plot the output voltage of your design (loaded) and measure the ripple.
 

·              Line input voltage: 117 Vrms

·              Regulated output voltage: 5 VDC + 5%

·              Load: resistive

·              Power Consumed by the Load: 175 mWDC

·              Indicator: A red LED must be used to indicate that the regulated output voltage is available to the load.

·              Ripple: minimum


 
 
 

3.-  Analysis of Results

Explain the design considerations and characteristics of each of the circuits in this experiment:
a) for the Zener regulator,     and
b) for the 5 VDC regulator