Graymark 803 User manual

POWERSUPPLY
0esigned and pmted in U.S.A.
Dr
I
Subsidiary of Buck Engineering Co., lnc.
tNTEFINATIclNAL,INC. 7I
L:'',
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INTRODUCTION
Your model 803 is specially designed for applications requiring a low voltage DC
power source. lt provides a continuously variable output of 0-15 Vdc at up to
300mA of current at full load. lt is ideal for use as a battery eliminator for
tr"ansistor radios, amplifiers, oscillators, etc. or you may use it as a convenient
voltage source for designing, experimenting, repairing and testing low voltage
semiconductor devices and circu its.
Your Power Supply is constructed in three PHASES, which will allow you to
experience many fascinating and meaningful experiments and will give you a
solid foundation in voltage rectif ication and power supply design.
PHASE I consists of constructing the unit in a breadboard form. Breadboarding is
a common technique used by electronic engineers and technicians in industry.
By using this technique, you achieve an over-all assembly of the circuit, which
demonstrates the inter-relationship of components as well as gives you easy
access for circuit testing. Thus, the construction and testing of PHASE I enables
you to understand the HOW and WHY of the unit's circuitry. If you are
constructing this proiect without the supervision of an instructor, you may omit
PHASE I and go directly to PHASE ll.
PHASE ll is, industrially speaking, the assembly operation. This phase is con-
cerned with arranging the components and fittings onto the chassis. This phase
will provide you with experiences such as, component identif ication, component
mounting, solder techniques, lead dress, and final assembly into the plastic
cabinet.
PHASE lll provides you with Operation tnstructions, Product Specif ications,
Learning Experience and Skill Development Review, and Review Evaluation. At
the back of this book is a section on servicing and parts replacement, which gives
a Service Flow Chart for your use in troubleshooting problems and gives
information on ordering replacement parts and on f actory servicing.
You are now ready to start constructing your power supply. Follow the in-
structions closely and you will have a worthwhile project, one that you can be
proud of and one that you will enjoy assembling.
TOOL REOUIREMENT
lllustrated below are the tools necessary to assemble your project. Additional
tools, such as nut drivers, pliers, and soldering aids, make circuit assembly easier, but are not required.
WIRE STRIPPER
SCREWDRIVERS, PHILLIPS HEAD
1-LARGE
SCREWDRIVERS, 1 - Ta" BLADE
1 -V8" BLADE
DIAGONAL CUTTERS
GRAYMARK INTERNATIONAL, INC.
SUBSIDIARY OF BUCK ENGINEERINC CO. INC.
2
P/N 61S4U rc
All righa reserued. This book ot patts thereol may not be reproduced in
any torm without violating the copyright law. Printed in U.S.A.
LONG NOSE PLIERS

PROGRESS GUIDE
-: rurpose of this Progress Cuide is to allow you to keep
.- rccurate record of your progress in construicting and
- - -:rstanding the electronic fundamenta!s contained in this
:- ict. To develop this basic understanding, be sure to
.,,=--lble this project in the sequence outlined below. Do
- : rroceed to the next experience until the previous one is
fully understood.
If the porver supply is being built for a school project, you
should obtain your instructor's initials at the completion of
each learning experience. The Final Evaluation is provided
so that your instructor can indicate your degree of achieve-
ment on the entire project.
rur Narne:
PARTS IDENTIFICATION
AND INVENTORY EXPERIENCE
SOLDERING EXPERIENCE
TRANSFORMER EXPERI ENCE
Construction
Instrumentation And Measurement
FULL-WAVE RECTIFIER EXPERIENCE
Construction
lnstrumentation And Measurement
FILTER CIRCUIT EXPERIENCE
Construction
lnstrumentation And Measurement
VOLTAGE CONTROL EXPERIENCE
Construction
Instrumentation And Measurement
PHASE II
CHASSIS ASSEMBLY
CHASSIS CONSTRUCTION
CIRCUIT TEST
CABINET ASSEMBLY
PHASE III
EVALUATION
REVIEW EVALUATION
FINAL EVALUATION
EVALUATION INSTRUCTOR'S
INITIALS
PHASE I
BREADBOARD

PARTS LIST wooel 803 Power Supply
ktl PART
NO. REPLAGEMENT PRICE
$1.s0
.25
1.00
1.00
2.00
*Attached to Panel
PARTS IDENTIFICATION
DESCRIPTION
Potentiometer, 10K ohms, w/lockwasher
Resistor, fixed, 820 ohms, VzW, 10o/o
Besistor, fixed, 1K ohms, %W, 10%
Capacitor, electrolytic, 100 pF, 35WV
Capacitor, ceramic disc, .02 iiF, 50V, (marked223)z
Capacitor, electrolytic, 470 pF, 16WV
Diode, silicon, power,50 PlV, 1A
Diode, zener, 16V
nsistor, power, with 2-insulatingwashers-
Transtormer, power, P :117Y, S : 40V, at 135 mA"
Terminal Strip, 4P-l
Line Cord, AC, 2-conductor, with molded plug
Knob, plastic
Line cord stopper, plastic
Terminal post, with mounting hardware, red
Terminal post, with mounting hardware, black
Plastic tubing, Black,5" length
Plastic tubing, clear, '1 "
wire, 1-red, 1-blue and 1-yellow
Solder, rosin core, 60l40
Self-tapping screw
Washer, shoulder, insulating
Washer, f lat, insulating
Panel, steel
Cabinet, plastic
lnstruction Manual
RESISTOR
r-\ \r
S-----)
\ DISo cAPAClroR
KNOB SELF-TAPPING SCREW
005*€BM,NAL
POST TERMINAL STRIP
,>. 6, @
\d.,*E coRD V/FLAr V.fi,?Bh?.*-
TRANSFORM ER
r-L
l'
ELECTROLYTIC
CAPACITOR
ZENER DIODE STOPPER WASHER
5.00
1.00
.50 set
.10 ea.
.-l-
r-L\
VY
/- \
NPN TRANSISTOR
--x--
I PoTENTToMETER

POWER
(AC)
SCHEMATTC DIAGRAM c2.
1st COLOR 2nd COLOR 3rd COLOR
BAND COLOR FIRST FIGURE SECOND FIGURE MULTIPLIER
OUTPUT
(DC)
RESISTOR COLOR CODE
. First color (color nearest the end of the resistor) represents the first figure in the resistor value
o Second color represents the second figure in the resistor value.
o Third color represents the multiplier of the first two figures.
. Fourth color represents the resistor tolerance. 4ih coloR
TOLERANCE
BLOCK DIAGRAM
NO COLOR
SILVER 10%
GOLD
BLACK
BROWN
RED 100
1,000
ORANGE
YELLOW 10,000
GREEN 100,000
BLUE 1,000,000
VIOLET 10,000,000
GRAY 100,000,000
WHITE 1,000,000,000
Red Violet Orange
27000
Creen Blue Red
5600
Silver
1O"/o :27000 or 27K ohm,10%
Silver
10o/o : 5600 or 5.6K ohm,'10%
EXAMPLE:
20"/"
T1
117Y
"Hl
LJ
5

SOLDERING EXPERIENCE
For this project to w,ork properlv, you rnust have good
solder connections. lf you have not had experience in
soldering, it is suggested that beiore you start assembl-
ing this project, you practice nraking solder connections
with odd lengths of rvire and used components. Observe
the following rules for proper soldering techniques.
l. Use a 30-to-5O-watt pencil type soldering iron. Do
not use a soldering gun.
2. Use only rosin core solder as supplied with your
project. The use of any other types of solder will
void your warranty. lf additional solder is requir"ed,
use only 60-.10 rosin core, such as Kester ,1.1. Dt)
NOT USE ACID CORE SOLDER or paste f luxes.
3. Be sure the tip of the iron is well tinned (coated
with a thin layer of molten solder) so that it will
properly conduct heat. To keep the tip clean, wipe
it from trme to time with a damp sponge or cloth.
(See Fig. 5.) Do not clean on a sal ammonia block.
,1. Before soldering, be sure all connection points
such as wire leads, terminal lugs, and printed cir-
cuit (p.c.) islands are clean and free of oxidation.
Trn wire leads before connecting them into the
c ircu it.
5. Whenever possible,.attach wire leads onto terminal
lugs by forming tight mechanical connections
before you apply solder.
6. Wear safety glasses while unsoldering and solder-
ing to avoid eye injury caused by a hot solder
splash or flying bits of wrre leads.
7. Position the flat side of the soldering iron firmly
against thc wjre lead and terminal to preheat the
metal parts to be soldered. (See Fig. 6)
B. While the connection is being heated, apply the
solder. Do not apply the solder directly onto the
tip of the iron. Remove the solder feed w,hen enough
molten solder has been applied to form a thrn coat-
ing on all nretal parts in the connection. (See Fig.
7.\
9. After the solder feed has been removed, continue
to heat ihe connection for an lNSTANT...this will
aid the flow of molten solder .tnd insure ag.rinst
flux pockets. Next, remove the iron from the c-on-
nection in a smooth motion.
10. Wait until the solder has cooled (solidified) before
testing the connection. A properly soldered con-
nection will have a good fi llet contour and a smooth
bright finish. (See Fig. 8.)
Lead dress and placement of ccmponents is also im-
portant. All wiring or parts placement should be as neat
as possible. See Fig. 9, 10, 1-l, and 12 for examples
of component placement and solder connections.
Have your instructor initial your Progress Cuide.
APPLYING SOLDER
'i,j.
FIG.7
CLEANING TIP
I
.l:r
''t...;yffi
FIG. 5
PREHEAT
FIG.6
SOLDER FLOW
FIG. 8
CORRECT
FtG.10
CORRECT
FtG. 11
m
_ i/_.-_.-
-t

PHASE I
BREADBOARD
tn this phase,you will have an opportunity to construct an experimental
breadboard similar to that used by engineers and technicians in industry.
A breadboard is a layout of electronic parts, wired in such a way that
the parts may be easily added or removed during experimental work.
DISCUSSION
Your Model 803 solid-state Power Supply consists of four
stages of circuitry: power transformer circuit, rectifier circuit,
filter circuit, and voltage control circuit. ln this phase you
will study the operation of your power supply by bread-
boarding one stage at a time.
TRANSFORMER EXPERIENCE
DISCUSSION
A transformer is an alternating current (AC) device that
transfers electrical energy from one circuit to another. lt is
usually used to STEP UP or to STEP DOWN an AC voltage.
ln its basic form, the transformer consists of two coils of
wire wound around an iron core. One coil is connected to
the AC source voltage and is called the PRIMARY winding;
the other coil is called the SECONDARY winding and pro-
vides the proper supply voltage.
The transformer used in this power supply is a step-down
transformer with a center-tap on the secondary winding,
as illustrated by the schematic symbol shown in Fig. A.
The application of two important laws in electricity make
transformers possible. They are: (1) An electric current flow-
MAGNETIC FIELD
ing through a coil produces a magnetic field that varies w'ith
the current; and (2) A magnetic field cutting across the wires
in a coil induces a voltage in the coil. Transformer action is
illustrated in Fig. B. It shows that the changing magnetic
field, created by the varying current in the primary winding,
induces a voltage in the secondary winding as the magnetic
field cuts across the turns of wire in this coil.
The relationship between the input voltage (primary) and
the output voltage (secondary) is determined by the number
of turns of wire in the primary and the number of turns of
wire in the secondary. This relationship is called the TURNS-
RATIO and is expressed mathematically as,
Eprimary _ N primary
Esecondary " N secondary
where,
E is voltage and N the number of turns.
For example: a transformer has 1,000 turns in the primary
and 500 turns in the secondary. lf a voltage of 1-10 volts AC
is applied to the primary, the secondary voltage will be 55
volts AC.
That is, 110 '1000
tsecondary 500
Esecondary : -ry
1000
Esecondary : 55 V
CONSTRUCTION
Cut out and fasten the BREADBOARD SCHEMATIC on page
23 to a flat piece of wood. This will serve as a breadboard
base upon which you will construct your experimental cir-
cuits. You will need to obtain the following items not fur-
nished with your project: (1) Twelve copper tacks (or brass
brads); (2) A 12-inch length of bare copper wire; and (3)
Four pieces of hookup wire, each 5-inches in length. 'DO
NOT CUT THE LEADS of any components unless instructed
to do so, because these components will be used for con-
structing other circuits. Caution: Do not disturb the mount-
ing of transistor Q1 . However, if it becomes necessary to
remove it, be sure the insulating washers are replaced
properly.
-- 1. Insert a tack into the breadboard at X marks 1
through 12 on the schematic.
FIG. ,ll,tlll|llll,ll,lllllll,l,]ll|l|lill,t,:l|llIl|lllllll|
CENTER-TAP
PRIMARY
WINDING
SECONDARY
WINDING
STEP-DOWN
FIG. A

CLEAR
PLASTIC
TUBING
- 3. Cut a 13/t-inch length of bare wire. Connect
solder this wire to tacks 6 and 7 to form bus
D
4. Cut a 73/+-inch length of bare wire. Connect
solder this wire to tacks 2, B, and 12 to lorm
wire "C".
FIG. C
2. Cut a 2-inch length of bare wire (not f urnished
with project). Connect and solder it to tacks 4 and
5. (Refer to Fig. C.) This wire will be referred to as
bus wire "A".
$>onavr'ranqUQDEL 8O3 POWER SUPPLY
117 Y
50-60 Hz
and
wire
and
bus
BREADBOARD SCHEMATIC
a--g
Y4 BUSWIREA X5 a,^F
irrl# jr,,,",,;,,;# ;i:i:i.,i*,iiijit,.?t*i+.;ttli$
*_ b lnsert 21./t -inches of the line cord through the
hole in the front panel Position the two por-
tions of the line cord stopper around the
cord where it extends out the front of the
panel. Next, r-rsing pliers, insert the stopper
into the hole in the panel lt should snap into
place. (Refer to Fig E2)
- c Cut the piece of clear plastic tubing in half
Slip one piece over each line cord lead. Con-
nect one lead to lug A of the transf ormer and
solder (solder-'1 ). Connect the other iead to
Iug B of the transformer and solder (solder-
1). Slip the tubing down over the 2 lugs to
insulate them (Refer to Fig. E3)
- d. Obtain four 5-inch lengths of hookup n,ire
Strip l/a-inch of insulation from both ends
of each wire and tin.
- e. Connect and solder one of these wires be-
tween lug E on the secondary winding of the
transf ormer and tack 1.
- f Connect and solder another wire between
lug D and tack 2.
- g Connect and solder another wire between
lug C and tack 3.
- 6. This completes the construction of the power trans-
former circuit. Have instructor initial ProgressCuide
FIG. D
- 5 Wire the power transformer (T1) to the breadboard
as follows: (Refer to Fie D)
-a. Separate the two leads of the AC line cord
lor 11h-inch f rom the end. Next, strip %-
inch of insulation from the end of each lead,
twist the strands together, and tin (coat with
a thin layer of solder) (Ref er to Frg E 1)
til-,.,.
+Eo"cg?D\\\h ctib
\ dv-
(@51/7ivs::
'a4u
FIG. E2
FIG. E1

RUMENTATION & MEASUREMENT
: zie about to perform LIVE VOLTACE TESTS on yoLtr
actoard circuit. Remember that, when properly used,
-:icity is a useful servant of man, but when misused,
::.icity is very dangerous and can cause severe bodily
t. Therefore, always use case when working with elec-
,'l, and observe these ru/es.
:'tc!ug circuit from power source EEFORE changing
::eier /eads or wiring.
:-;e on/y one hand when performing tests.
-(:and on an insulated sttr{ace when working on and test-
'rg ihe breadboard circuit.
'i at'ailable, use an isalation transfc:rmer for added safety'
i,l=ep the breadboard on a wooden ar ungrould-1d sur;
-:ce rvhen working on or testing the circuit. NEVER work
-^ a metal surlace.
-- '\'K SAFETY.
- 1. Voltage Test
For this test you will need a volt-ohm-milliammeter
(VOM). The purpose of this test is to demonstrate
the voltage step-down action of transfgrmer T1 by
measuring and comparing the primary. and secon-
dary voltages.
--a. Adjust the VOM to a range that will measure
- -e. UNPLUC THE LINE CORD.
- -f . Next, connect the VOM test probes to tacks
-'l and 2 so you can measure the voltage
between one side of the secondary winding
and the center-tap. PIug in the Iine cord.
Read and record this voltage (Ect 1) in the
space provided in Fig. C. lt should be ap-
proximately 25 volts AC.
g. UNPLUC THE LINE CORD.
-h. ,\4ove the VON,1 test probe from tack 1 to
tack 3 so you can measure the voltage be-
tween the other side of the secondary wind-
ing and the center-tap. Plug in the line cord.
Read and record this voltage (Ect 2) in the
space pr"ovided in Fig. C. lt should be the
same as fct 7.
- -i.UNPLUG THE LINE CORD. Remove the
VO,\4 test probes from the breadboard.
-j. Refer to Fig. G and add Ect-1 to Ect 2 and
. ls this volt-
record their sum
age about the same as Es?
It should tie.
Have instructor initial your Progress Cuide.
Adjust the VOM
FIG. F
125 iolts AC, then, connect the test probes
to the primary ,.vinding Iugs (A&B) oI T1,
as shorvn in l-ig F.
b. Plug the line cord into a 1-l,0-120 volt re-
ceptacle. RearJ ancl recorcJ this primlr;
voltage (Ep) in thc space provided in Fig. C.
tt shoulC be approximately 115 volts AC.
c. UNPLUC THE LINE CORD.
d. Move the VOLI test probes to tacks 1 and 3
on the breaciboard so you can measure the
seconclarr.,r,oltage. PlLig in the line cord.
Read and record the secondary r,oltage (Es)
in the space provided in Fig. C" It shoulcl
be approxtnlzlsltl 50 volts AC.
PRIN4ARY SECONDABY
Ectr:-1
c-
LP-
-
FIG, G
E5 '-
9

FULL-WAVE RECTIFIER EXPERIENCE
DISCUSSION
The process of changing alternating current (AC) to direct
current (DC) is called rectification. A full-wave rectifier uses
both halves of the AC cycle in the rectification process. That
is, it produces one DC voltage pulse for each one-half cycle
of AC, as illustrated in Fig. H.
Using the illustration in Fig. l, trace the path of current flow
through the full-wave rectifier during one-half of the AC
cycle. Remember, current always flows in the direction op-
posite to the arrow in the diode symbol (cathode to anode) .
Using the illustration in Fig. l, trace the path of current flow
through the full-wave rectifier during the other half o{ the
AC cycle. Notice that only one-half of the secondary wind-
ing of the transformer is used at any one time.
From this, you can see that the DC output voltage of r', .'
full-wave rectifier varies in amplitude between zero ?'
some maximum value. Since a pure DC is desirab!e ' '
proper operation of most electronic equipment, a spe.
circuit must be added to the rectifier to smooth out t-.
pulses. These circuits are called filter circuits (you will a,: -
a filter to this rectifier in the next stage) . The output o:.
power supplv is never pure DC voltage, but rather conta'-.
some fluctuation, referred to as "ripple". A common measL. -.
of the smoothness of the DC voltage is the "percent.'-
ripple", w.hich is a ratio of the ripple voltage (rms) and i:-
average DC voltage. This is expressed mathematicall',, 25
%-of-ripple _ Ermsof Ripple Voltage *100
E average
CONSTRUCTION
- 1. Solder the ANODE lead of rectifier diode CR1 i:
tack 1, as shown in Fig. K. (Refer to Fig. L for dioc=
lead identification).
2. Solder the ANODE lead of rectifier diode CR2 :
tack 3.
- - 3. Solder the CATHODE leads (leads nearest the colc:
bands) of both CR'l and CR2 to tack 4. (Refer tr,
Fig. K)
- 4. Temporarily solder the 1K resistor (brown-black-
red) between bus wires A and C. This resistor lr'r
temporarily be used as a load. A "load" is a devict
that draws current and consumes energy. lt is usec,
to simulate actual operating conditions.
5. This completes the construction of the full-wate
rectifier circuit. Have instructor initial your Progress
Cuide.
INSTRUMENTATION AND MEASUREMENT
- - 1. Diode Resistance Test
For this test you will need a VOM. The purpose c'
this test is to show,that current will flow through a
diode in only one direction.
a. Adjust a VOM to the R x 1 resistance range.
Connect the NECATIVE (-) test probe to
the CATHODE of diode CR1 and the POSI-
TIVE (+) test probe to the ANODE, as
shown in Fig. M.
b. Read and record this resistance reading:
- c. Reverse the test probes so that the NECA-
TIVE ( ) probe is connected to the ANODE
of diode CR1 and the POSITIVE (l) probe
is connected to the CATHODE. Also, change
the VOM to the R x 100K range.
M\N., PULSATNG
1-CYCLE
FLUCTUATING
DC nrrnn^
RECTIFIED
FILTERED
=l
jli
FIG.
d. Read and record this
Remove resistance reading test probes.
?
E
10 FIG. J
\-/
o<
lt
FIG. H
;o

DIODE
COLOR
BAND
FIG. L
----e. The resistance reading recorded in step b
should be very low and the resistance re-
corded in step cl should be extremely high.
Are they? You can see {rom
this test, that a diode provides a path of
very Iow resistance for current in one direc-
tion and blocks nearly all current in the
other dircction.
2. Percent-of-Ripple Test - No Filter
For this test you will need a VTVM (vacuum-tube
voltmeter or TVM (transistorized voltmeter) . The
purpose of this test is to determine the percent-of-
Ripple of the pulsating DC from the fuil-wave
rectifier.
-a.
Adjust the VTVM to a range that wili meas-
ure 50 volts DC. Connect the NECATIVE (-)
test probe to bus r'vire C, and the POSITIVE
(-) DC probe to bus r,r,ire A. (Refer to Fig.
K).
-tr.
PIug in the Iine cord. Read and recorcl this
voitage measurement: -.lt should
be about 20 ve,tlts DC. This is the "E3ys12gs
voltage".
c. UNPLUC THE LINE CORD. Then, change the
meter to a range that will measure 15 volts
AC, and substitute the AC test probe for the
DC probe connected to bus wire A.
d. Plug in the line cord. Read and record this
voltage measurement: . lt should
be about'l 0 volts AC. This is the "E1mq of
Ripple Voltage".
e. UNPLUC THE LINE CORD. Remove the test
probes from the breadboard.
f . In the space provided belor,v, rvrite the equa-
tion fo r calcu lati n g percent-of-Ri pple. (ilefer
to Full-wave Rectifier Discussion)
(1) %-of-nipple :x -100
g. In the space provided belorv, calculate the
percent-of-Ripple by substituting the proper
voitages for the letter symbols used in the
equation. The E165 of Ripple voltage is the
AC measurement obtained in step d above,
and the Eaverage ','oltage is the DC measure-
ment that was obtained in step b.
(2) % Ripple
(3) % Ripple
(4) % Ripple -
The ok-ol-Ripple sltould be about 50oio
- 3. Have instructor initial your Progress Cuide.
x 100
x 100
FIG. M
p>onava,ranx MODEL 8
\ BREADBOARD
FIG. K
11

FILTER CIRCUIT EXPERIENCE
DISCUSSION
Since most electronic equipment recuires a smooth DC
voltage for proper operation, the outpirt of a rer.tifier can-
not be applied directly to the ecluipnrent. YoLrr ,\loclel 80j
Power Supply uses a capacitance Ii Iter circuit to smooth out
the pulsations. ln this circuit, the capacitor acts similar to a
storage tank. lt stores an elecirical voltage r,vhen the rectilier
output voltage is high and discharges 'when the rectifier
voltage drops. This has the eficct oi li.tttening out lhe peaks
of the pulses and filling in the valleys betr,veen them. This
results in a relatively smooth DC voltage. (Refer to Fig. ll .)
CONSTRUCTION
- 1. Solder the POSITIVE lead of filter capacitor -'
100 7,F 35VDC, electrolytic, to bus wire A, anc --
NECATIVE (-) lead to bus wire C, as shoi^, - -
Fis N
-
2. This completes the construction of the fi Iter cr:
Have instructor initial your Progress Cuide.

INSTRUMENTATION & MEASUREMENT
')'ou are ai;ctri to ;;erfor-,';r ii/E Vi_)'LTt|,CL'{f_ST5.n t/.ar-.I,r
t:'eadbctarri circuit. fteren;,ber that, whtn pi-c;-ui,/ L't<ar'.
electricity is a u,cefl.ii .te,"vant af ma,t, t'tut tn,h*:r; rnisii.;eC, jt
ls clangerou-s and can cerr.re .sev€rr 'oodily har;tt as",rrelJ as
oe-stroy valuable e/ecir-onic equr;;rnent. fhei.ellre, alvva,vs
rse .aie 'or-hen r,r,,c,"k ing ,with e/ecIrjcit_u TfliNK .sAFffy.
- L Percent-of-Ripple Test - With Filterl
For this test you will need a VTVM or TVM. The
purpose of this test is to show the effect a filter has
in smoothing out the pulsating DC. This will be
done bry determining the percent-of-Ripple of the
filtered DC voltage, and then comparing this per-
centaBe to the percent-of-Ripple found in the pre-
vious stage (rectified DC without filtering).
-a. Adjust the VTVM to a range that will meas-
ure 50 volts DC, Connect the NECATIVE (-)
test probe to bus wire C, and the POSITIVE
(+) DC test probe to bus wire A. (Refer to
Fig. N)
-b. PIug in the line cord. Read and record this
voltage measurement: --. It should
be about 32 volts DC. This is the "Elystlgg
voltage".
-c. UNPLUC THE LINE CORD. Then, change the
meter to a range that will measure 1 volt
AC, and substitute the AC test probe for the
DC probe connected to bus wire A.
-d. Plug in the line cord. Read and record this
voltage measurement: lt should
be about 0.35 volts AC. This is the "Eyp5 6f
Ripple voltage".
-e. UNPLUG THE LINE CORD. Then, remove
the test probes from the breadboard.
-f ln the spaces provided below, calculate the
percent-of-Ripple of the filtered DC voltage
by substituting the proper voltages into the
equation. (Refer to previous steps b and d
for the voltage readings)
(1) % Ripple -Ey;ps of ripple voltage
OPTIONAL EXPERIENCE
For this test you wili need an oscilloscope. The purpose of
this test is to visually show the rectification process and the
effect the filter capacitor has on smoothing the DC voltage.
--l . Solder the lK ohm resistor betlveen bus wires A
anrl C
2. Unsolder the POSITIVE lead of the filter capacitor
(c1).
. 3. Connect the CROUND Iead of the scope to br-rs
wire C and the VERTICAL INPUT probe to tack -1.
4. Plug in the Iine cord and adjust the scope to display
the AC cycle. It should be similar to Fig. O.
5" UNPLUC THE LINE CORD. Move the VERTICAL lN-
PUT probe to bus wire A.
6. Plug in the line cord and adjust the scope to display
the pulsaiing DC. It should be similar to Fig. P. You
w,ill note that only the top or positive half of the
cycle now appears.
7. UNPLUC THE LINE CORD. R.esolder the filter ca-
pacitor to bus wire A.
8. PIug in the line cord ar.rd adjust the scope to display
the filtered DC. It should be similar to Fig. Q. You
will note that the peaks have been drasticaliy re-
duced to nearly a straight line.
9. UNPLUC THE LINE CORD. Remove the scope leads,
and the IK ohm resistor from bus rvires A and C.
(2) % Ripple :
(3) % Ripple :
Eaverage x 100
x 100
x 100
(4) % Ripple :
T he'k -of-Ri pple should be about 1 o/o .
Compare this %-of-R.ipple to that obtained
in the previous stage (step 29, Page11 ). lt is
easy to see from this test that a simple filter
circuit consisting of only a single capacitor
can have a great effect in smoothing out
the pulsating DC voltage.
--9. Unsolder the 1K ohm resistor from bus wires
A and C.
2. Have instructor initial your Progress Cuide.
AC
I
FIG. O
FLUCTUATING DC
FILTERED
PULSATING DC
FIG. Q13

VOLTAGE CONTROL EXPERIENCE
DISCUSSION
In this experience you will construct a variable voltage
power supply by adding a voltage control circuit to the
b read boa rd.
In this circuit, transistor Q1 acts lil<e a variable resistor con-
nected in series with a "load". Zener diode CR3 is used as
a bias voltage reference. That is, it maintains 16 volts across
potentiometer R1. The output voltage level is controlled by
the amount of bias voltage on the base of the transistor.
Potentiometer R-1 controls this bias voltage. The greater the
bias voltage, the greater the or-rtput voltage.
CONSTRUCTION
- 1. Connect transistor Ql to the breadboard as follows:
(Refer to Figs. R & S).
a. Strip 1/q-inch of insulation from both ends
of the RED, BLUE, and YELLOW hookup
wires that are packaged in your project.
Solder the CATHODE lead (lead nearest the co c'
band) of zener diode CR3 to tack 9 and the ANCD:
Iead to bus wire C.
Cut the remaining 5-inch piece of hookup wire i-
2-inches in Iength and strip 1/+-inch of insulat:c -
from both ends, then tin. Connect and solder be-
tween tack 11 and bus wire C.
- 5. Solder potentiometer R-l to tacks 9, 10, & 1-1 , a..
shown in Fig. R.
6. Solder anti-oscillation capacito r C2, .02y.F, betrr ee-
bus wire A and bus wire B. (Refer to Fig. R)
7. Solder bleeder resistor R3, 1K ohms (brorvn-blaci:-
red), betw'een bus wire B and bus wire C, as sho',',-
This resistor is used to "bleed-off" any charge tl . -
may remain on capacitor C3 after the power supp
is turned off.
8. Solder output capacitor C3,47O1tF 16 VDC, bett'ee-
bus wire B and bus wire C. This capacitor is use
to add additional filtering to your power supp"
9. Have instructor initial your Progress Cuide.
__ 3.
_4.
FIG, R
b. Connect and solder the RED wire to the
EMITTER lead of Q1. (Refer to Fig. S for lead
identif ication.)
- ..c. Connect and solder the BLUE wire to the
COLLECTOR lead (center iead).
d. Connect and solder the YELLOW wire to
the BASE lead.
- e. Solder the free end of the RED wire to tack
6.
f . Solder the f ree end of the B LUE wire to tack 5.
g. Solder the free end of the YELLOW wire to
tack 10.
2. Connect and solder bias resistor R2, 820 ohms
(gray-red-brown), between l-.us wire A and tack 9.
This resistor is used to limit the zener and base
cu rrents.
14
COLLECTOR
FIG. S

,STRUMENTATION & MEASUREMENT
1. Output Voltage Test
For this test you will need two VOM's. The purpose
of this test is to show the effect that transistor Q1
has on controlling the output voltage.
a. Adjust one VOM to the 50 volt DC range.
Connect the NECATIVE (-) test probe to
bus wire C, and the POSITIVE (*) probe to
bus wire A, as shown in Fig. R. This will
measure the output voltage (V") of the
rectifier and filter circuit.
-b
Plug in the line cord. Read and record this
voltage measurement: V., :
It should be about 30-35 volts DC
c. UNPLUC THE LINE CORD. Then, move the
NECATIVE (-) VOM test probe to bus wire
B. (Refer to Fig. T). This meter will be used
to measure the COLLECTOR-EMITTER volt-
age (V,.") across the transistor.
- d Adjust another VOM to the 50 volt DC
range. Connect the NECATIVE (- ) test
probe to tack 12, and connect the POSITIVE
(-l1 probe to tack 7. (Refer to Fig. T). This
meter will be used to measure the output
voltage of your variable power supply.
e. Plug in the line cord. Next, rotate the shaft
of potentiometer R-l fully counterclockwise.
The output voltage (V.) should now be
zero. Is it? - Measure the col-
lector-emitter voltage (V"") and record in
the space provided in Table I.
--,f. Next, add together V. and V"" and place
the sum in the space provided in Table I.
-9. Complete Table I by adjusting the poten-
tiometer for each of the output voltages
(V") listed in the table. Then, record a V""
measurement for each of these output
voltage settings. Next, total each combina-
tion of V" and V"". Is the total for each com-
bination approximately the same?-.
They should %e. You can see from this test
that the output voltage of the rectifiei and
filter circuit is divided between (1) the tran-
sistor and (2) the device connected to the
output of the power supply. And, by vary-
ing the base bias voltage, the collector-
emitter resistance changes, causing a change
in the collector-emitter voltage.
-h. UNPLUG THE LINE CORD and remove the
VOM test leads from the breadboard circuit.
This completes PHASE l. Check with your instructor
for additional tests and experiments that he may
want you to make, using your breadboard circuit.
Unsolder the components from the breadboard (by
reheating the connections), one at a time. Also,
unsolder the line cord from the power transformer
and all pieces of hookup wire that are soldered to
components.
Have instructor initial your Progress Guide. 15
ls this total voltage
as the voltage read
It should be.
approximately the same
in step b above:-.
TABLE I
__ 2.
_3.
_4.
p>onara,ranx MODEL

PHASE II
ASSEMBLY PROCEDURE
CIRCUIT ASSEMBLY
Do not solder any w'ires or component leads until instructed
to do so. After all wires and leads have been connected to a
particular lug or terminal, it should then be soldered. To
assist you, the word "solder" and a number in parenthesis
O will indicate the number of leads that are supposed to be
connected to the lug at the time it is soldered. Example:
(solder-2) means two leads are to be soldered to the Iug.
CAUTION: DO NOT DISTURB MOUNT/NC OF TRANS/S-
TOR Q7. HOWEVER, tF tT BECOMES NECESSARy TO Rt-
MOVE IT, BE SURE THE iNSUtAIlNC WA5I1ERs ARE RE-
PLACED PROPERtY.
Assemble your project as follows:
-l . Mount potentiometer R1, -1 0K ohms, to the front
panel and position the three lugs as shown in Fig. 1.
2. Mount the RED terminal post to the front panei
using the two insulating washers as shown in Fig.2.
Position the lug as shown in Fig.3 and bend the
solder lug up (away {rom the panel).
- 3. Mount the BLACK terminal post to the front panel
as shown in Fig.2. Position the lug as shown in
Fig.3 and bend the solder lLrg up (away from the
panel).
4. Bend the BASE lead of transistor Q1 (refer to Fig. 4
for lead identificatron) to connect it to lug B (center
Iug) of the potentiometer and solder (solder-1).
(Refer to Fig. 5.)
| -*u,
d
A-.- ryASHER
/---/
LOCK WASHER
BLACK TERMINAL
FIG. 2
- 5. Cut a 2lh-inch length of RED l-rookup wire and
strip /.r-inch of insulation from both ends. Connect
one end to the E/V1 ITTER lead of the transistorand
solder (solder-1). (Refer to Figs. 4 and 5.) Con nect
the other end to lug D of the terminal strip as in
Fig.5.
6. Cut a 1-inch length of RED hookup r'vire and strip
1,/a-inch of insr-r lation from both ends. Connect one
end to tl-re solder lug of the RED (positive) ter-
minal post and solder (solder-1). Connect the other
end to Iug D of the terminal strip.
7. Cut a 3-inch length of BLL.I-E hookup rvire and strip
%-inch of insulation from both ends. Connect one
end to the COLLECTOR lead of the transistor and
solder (solder---t). (Refer to Fig. 5.) Connect the
other end to lug A of the termina! strip.
B. Cr-rt a 2-inch length YELLOW hookup rvire and strip
%-inch of insulation from both ends. Connect one
end to lug D of transformer T1 and solder (solder-
1). Connect the other end to lug A of the poten-
tiometer. (Refer to Fig. 5.)
- 9. Cut another 2-inch length of YELLOW hookup wire
and strip %-inch of insulation from both ends.
Connect one end to lug A of the potentiometer.
SOLDER LUG
m____
\-7 RED
p re nvrNar- eosr
t=f-T:
PI- C
\/il
/\
@
16
POTENTIOMETER R1
FIG. 1FIG. 3
SOLDER LUG
FRONT PANEL
).t-[
.-a
SHOULDER
WASHER
FLAT WASHER
SOLDER
LUG -/l
o

Connect the other encl to the solder lLrg on the
BLACK (neeative) terminal Jrost.
-l il. Cut bc.,th leacjs of resistor R2, E20 ohnr:. (gray-red-
brolvrr), to i+-inch lcngth. Cut lr,vo ltieces of black
spaghetti iLrbing, each 1,'! -inch Iength. Slip one
piece or",er cach of ihe resistor learJs. Connect ont.l
lead to lLrg C oi the potentiomete r and the r.,iirei'
lead to iL-ig i\ oi tlre ierminal stl.ip. (R.efer to Fis 7.\
-1 -1 . Cut both ieads of zener ciiocle CR3 to %-inch
length. Connect the CATIJODE Iead (lead nearest
the ccloi"band, as shor,vn in Fig.6) to IuE C of the
potentionre Ier ancl solcJer (solder-2). Connect the
ANODE lead to lug A oi the potentionreter ancl
solder (solder-3). (Rcfer to Fig. 7.)
12. Connect the ANODE lead of diode CR1 to lug E
: , -I.ECTOR FIG. 4
of the transformer and solder (solder-1). (Refer to
Figs. 6 and 7.) lnsert the CATHODE Iead (lead near-
est the color band) through lug B of the terminal
slrip and connecl it to lug A as shown in Fig.7.
13. Cut both leads of diode CnZ to %-inch length.
Connect the ANODE lead to lug C of the trans-
former and solder (solder--l). Connect the CATH-
ODE lead to lug B of the terminal strip.
14. Cut both leads of capacitor C2, .02 p,.F, to 3/c-inch
length. Connect one lead to Iug B of the terminal
strip and solder (solder-3). Connect the other lead
to lug D of the terminal strip.
15. Cut both leads of resistor R3, 1K ohms (brown-
black-red), to 1/z-inch length. Connect one lead to
Iug C of the terminal strip and the other lead to
lLrg D of the.tc,r.nrin.tl slrip.
-1[r. CLrt both leads of capacitor C3, 470 uF, to %-inch
length Connect the POSII IVE lead to lug D of the
terminal strip and solder (solcler'5) Connect the
other lead to the solder lug on the BLACK terminal
po5t, as shorvn inFig 7, and solder(solder-2)
l7 CLrt both leads of capacitor C1,100 uF, to %-inch
Iength Connect the POSITIVE iead to lug A of the
terrnrnal strrp and solder (solder-4) Connect the
other lead to lug C ot the terminal strip and solder
{'older-2r tRpter to I ig 7 t
lf breadboard rvas constructed, omit step-1 B
18. Scpar.rte the tu,o le;rd,s of thc Iine corcl ior 11l: -
inches ironr llrc encl. StriJr r,+ -inc.h oi insLt l.rti<tn
ironr the cncl of ltoth lcacls Tu.,ist together the
sLrancJs n'itlrin cac.h Icacl .rrrrJ tin. iReier to Fig B.)
DIODE
FIG. 5
EMITTER
'G
\ --r- /
\'l/
ANODE LEAD CATHODE
COLOR
BAND LEAD
FIG.6
19. lnsert 2%-inches of the Iine cord through the hoie
in the f ront panel. Position the two portions of the
Iine cord stopper around the cord where it extends
out the front of the panel. Next, using pliers, insert
the stopper into the hole in the panel. lt should
snap into place. (Refer to Fig. 9.)
20. Cut the piece of clear plastic tubing in half. Slip
one piece over each Iine cord lead. Connect one
lead to lug A of the transformer and solder (solder-
1). Connect tl-re other lead to lug B of the trans-
former ancl solder (solder-l ). Slip the tubing do,"r,n
over the 2 lr-rgs to insulate them. (Refer to Fig. 10.)
21. This conrpletes the circuit assembly of vour Cray-
mark ,\loclel 803 Pou,er Supply. Have instructor
initial your Progress Cuide.
FIG. B
,.......- LINE
LINE CORD
STOPPER
TRANSFORMER
C f n l\-tl]ol E=a( t\ C

TESTING
Before testing your Cravmark Power Supply, compare your
wiring to that shown in Fig. 7, and be sure you have made
good solder connections. For testing this unit you will need
a voltmeter. If no voltrneter is available you may simply test
your power supply by connecting it to a transistor radio as
described in Operating Procedure on page 19.
1. Rotate the potentiometer shaft f ully counterclock-
wise to the MIN position.
2. lnsert the line cord plug into a 110-120 VAC wall
receptacle.
-3. Adjust the voltmeter to the 0-50 volt DC range.
Then, connect the negative (-) meter lead of the
voltmeter to the negative (-) terminal post (black)
on the power supply and the positive (f ) meter
Iead to the positive ( 1-) terminal post (red).
4. The meter should now read 0 volt.
-5. Slowly rotate the potentiometer shaft to the full
clockwise position. The voltmeter should now read
between 15 and 1B volts DC. lf this voltage is not
obtained, UNPLUC THE LtNE CORD. recheck all
wiring, component placement, solder connections,
and then refer to the Service Flow Chart on page 22.
-6. This completes the testing of your Model 803 Power
Supply. UNPLUC THE LINE CORD. Have instr-
uctor initial your Progress Cuide.
Ql
(ou1
o-:<? /
CABINET ASSEMBLY
-1. Position the front panel onto the plastic cabinet and
align the mounting holes. Secure the panel to the
cabinet with four self-tapping screws (Phillips screw),
as shown in Fig. 11.
-2. Rotate the potentiometer shaft fully counterclock-
wise. Position the knob onto the shaft with the in-
'dicator line to the left pointing toward the "MlN"
position). Secure the knob by tightening the set-
scfew as shown in Fig. 12.
-3. This completes the cabinet assembly of your Model
803 Power Supply. Have instructor initialyour Pro-
gress Cuide.
CONTROLKNOB SCREWDRIVER
SETSCREW
Ctttra,ga
SELF.TAPPING MACHINE SCREW
@0,
-
18
F"Tav*r.Rr.
Ftc. 12
VO LTA, OE AO.-/ us r
FIG.11

PHASE III EVALUATION
OPERATING PROCEDURE
.r may use your Model 803 Power Supply for designing,
=,:erimenting, testing, repairing and operating many solid-
, ...:e devices. However, to obtain maximum operating re-
.- ., follow these simple instructions and suggestions.
: DERATING INSTRUCTIONS
. Rotate the voltage control knob fully counterclockwise to
.ne MiN position.
- r-sinB test leads or hookup wire, connect the Power
iupply to the electronic device to be operated. Be sure
:o observe polarity and to not exceed 300 mA current.
: rsert the line cord plug into a 110-120 volt AC recep-
:acl e.
- Slorvl;r rotate the voltage control knob in a clockwise
r-lirection until the desired voltage is obtained. (Refer to
C perati ng Suggestions below.)
Turn OFF the Power Supply by returning the voltage con-
tr-ol to the MIN position and then unplugging the line
cord from the wall receptacle.
TRAN
POWER SUPPLY
OPERATING SUGGESTIONS
o Should you desire to monitor the output voltage from
your Power Supply, connect a voltmeter to the circuit as
shown in Fig. 13.
. No voltage indications are shown on the control dial be-
cause the output voltage at any particular setting will vary
according to the current drawn by the device to which the
Power Supply is connected. However, you may wish to
make voltage markings on the dial for commonly used
devices by first connecting a voltmeter in the circuit as
shown in Fig. 13, adjusting the Power Supply for the re-
quired voltage, and then making a voltage mark on the
face of the dial.
SISTOR
RADIO
CAUTION: Your Power
Short circuits for only a
careful to avoid making
Supply is designed to withstand
short duration; therefore, be very
the wrong connections.
6)
V
frg gd
6aaY uAlt(
-4
BATTERY CONNECTION
FtG. 13 19

HOW YOUR PROJECT WORKS
Your Model 803 solid-state Power Supply consists of four
stages of circuitry: power transformer circuit, rectifier cir-
cuit, filter circuit, and voltage control circuit.
TRANSFORMER CIRCUIT
Transformer T1 is used to step
voltage to the voltage required
Por,ver Supply.
dorvn the 110-12A VAC line
for proper operation of the
RECTIFIER CIRCUIT
Diocles CRl and CR2 are rised as rectifiers. That is, they are
used to change the alternating current (AC) frorn the trans-
former to pulsating direct current (DC).
FILTER CIRCUIT
The fiiter circuit cctr.rsists of capacitors Cl and C3, and re-
sistor R.l. The1,3re used t9 srngttth out the pulsations of the
DC,"'oltage frorn the recifier cliocles.
UUN IHOL CIRCUIT
The control c ircLr it consisls of zener diode CR3, resistor R2,
pote,ntiorneter R-l , capacitor C2, and transistor Q1. The
transistor acts as a i,ariable resistor to control the outpirt
i,oltage and js, in turn, controlled by the potentiorneter.
20
LEARNING EXPERIENCE AND SKILL DEVELOPMENT REVIEW
This project has afforded you the opportunity of expanding your knowledge
of electronics and electrical devices through experiments and related techni-
cal informalion.
You will probably be surprised at the number of skills you have learned and
the amount of knowledge you have acquired from building this project, such
AS:
o ldentification of electronic components . What rectification is and does
o ldentification of schematic symbols o How transformers function
. How to read resistor color codes o How diodes function
. How to read schematic diagrams o Capacitance filtering
. How to read block diagrams . How to calculate
. How to solder properly percent-of-ripple
. use of hand tools o safety precautions
. Use of test equipment