Elenco Electronics SP-3B Assembly And Instruction Manual

SOLDER PRACTICE KIT

MODEL SP-3B

Assembly and Instruction Manual

Elenco®Electronics, Inc.

ight © 2005, 2001 b

yr

Cop

t of this book shall be reproduced b

No par

y Elenco

®

Electronics

y means;

y an

, Inc.

electronic

ights reser

All r

, photocopying, or otherwise without written permission from the publisher.

ved. Revised 2005 REV-F 753000

PARTS LIST

If you are a student, and any parts are missing or damaged, please see instructor or bookstore.
If you purchased this kit from a distributor, catalog, etc., please contact Elenco®Electronics (address/phone/e­mail is at the back of this manual) for additional assistance, if needed. DO NOT contact your place of purchase
as they will not be able to help you.

RESISTORS

Note: Please refer to page 7 for the resistor reading exercise. This will familiarize you with the resistor color
band coding.

Qty. Symbol Value Color Code Part #

2 R1, R7 100Ω 5% 1/4W brown-black-brown-gold 131000
2 R2, R8 150Ω 5% 1/4W brown-green-brown-gold 131500
2 R3, R9 200Ω 5% 1/4W red-black-brown-gold 132000
2 R4, R10 220Ω 5% 1/4W red-red-brown-gold 132200
2 R5, R11 330Ω 5% 1/4W orange-orange-brown-gold 133300
1 R13 18kΩ 5% 1/4W brown-gray-orange-gold 151800
1 R14 27kΩ 5% 1/4W red-violet-orange-gold 152700
1 R15 39kΩ 5% 1/4W orange-white-orange-gold 153900
1 R16 47kΩ 5% 1/4W yellow-violet-orange-gold 154700
2 R6, R12 56kΩ 5% 1/4W green-blue-orange-gold 155600

ellow-gold 161000

lack-y

1 R17

100kΩ 5% 1/4W bro
1 R18 120kΩ 5% 1/4W brown-red-yellow-gold 161200
1 R19 470kΩ 5% 1/4W yellow-violet-yellow-gold 164700
1 R20 680kΩ 5% 1/4W

wn-b

blue-g

ray-yellow-gold 166800

CAPACITORS

Qty. Symbol Value Description Part #

2 C1, C2 10µF 16V Electrolytic 271015

SEMICONDUCTORS

Qty. Symbol

2 Q1, Q2 2N3904 Transistor NPN 323904
2 LED1, LED2 Red LED (Light Emitting Diode) 350002

Value Description Part #

MISCELLANEOUS

Qty. Symbol Description Part #

1 PC Board 517042
1 SW1 Slide Switch 541102

U1 16-pin IC Socket 664016

1
1 Desoldering Wick 556000
1 Battery Snap 590098
36” Wire 22AWG Topcoat 814600
1
1

Color Code Calculator 9CC100

Solder Tube 9ST4

PARTS IDENTIFICATION

Resistor

Capacitor

Semiconductor

s

Miscellaneous

Electrolytic

LED T

ansistor

r

IC Soc

-1-

et 16-pin

k

Batter

y Snap

Solder

Wic

Slide Switch

k

Solder

IDENTIFYING RESISTOR VALUES

Use the following information as a guide in properly identifying the value of resistors.

BAND 1

1st Digit

Color Digit
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Gray 8
White 9

Note: Please refer to the
Resistor Reading Exercise
on page 7 before starting
assembly of your solder
practice kit.

BAND 2

2nd Digit

Color Digit
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Gray 8
White 9

2 Multiplier Tolerance

1

Multiplier

Color Multiplier
Black 1
Brown 10
Red 100
Orange 1,000
Yellow 10,000
Green 100,000
Blue 1,000,000
Silver 0.01
Gold 0.1

BANDS

Resistance

Tolerance

Color Tolerance
Silver +
Gold +5%
Brown +1%
Red +2%
Orange +3%
Green +
Blue +0.25%
Violet +0.1%

10%

0.5%

IDENTIFYING CAPACITOR VALUES

Capacitors will be identified by their capacitance value in pF (picofarads), nF (nanofarads), or µF (microfarads). Most
capacitors will have their actual value printed on them. Some capacitors may have their value printed in the following
manner. The maximum operating voltage may also be printed on the capacitor.

Multiplier

10µF 16V

For the No. 01234589
Multiply By 1 10 100 1k 10k 100k 0.01 0.1

Note: The letter “R” may be used at times
to signify a decimal point; as in 3R3 = 3.3

The letter M indicates a toler
The letter K indicates a tolerance of +
The letter J indicates a toler

103K

100V

First Digit
Second Digit
Multiplier

olerance

T

Maximum Working Voltage

ance of +20%

10%

ance of +5%

The value is 10 x 1,000 = 10,000pF or .01µF 100V

METRIC UNITS AND CONVERSIONS

viation Means Multiply Unit By Or

Abbre

p Pico .000000000001 10
n
µ micro .000001 10

m milli .001 10

– unit 1 10
k kilo 1,000 10

M

nano

mega

.000000001

1,000,000

10

10

-12

-9

-6

-3

0

3

6

1,000 pico units = 1 nano unit

1.

2. 1,000 nano units = 1 micro unit

3. 1,000 micro units= 1 milli unit
1,000 milli units = 1 unit

4.

5. 1,000 units = 1 kilo unit

6. 1,000 kilo units= 1 mega unit

-2-

INTRODUCTION

Almost every electronic device today has a printed
circuit board. Whether you are assembling a PC
board or repairing it, you must understand the basics
of working with these boards.

Good soldering requires practice and an
understanding of soldering principles. This solder
practice project will help you achieve good soldering
techniques, help you to become familiar with a
variety of electronic components, and provide you
with dynamic results. If the circuit is assembled and
soldered properly, two LEDs will alternately flash.

Solder is identified by the ratio of tin-to-lead. The
most common ratios are 63/37, 60/40, and 50/50.
The first number indicates the amount of tin and the
second is lead. A 63/37 solder has 63% tin and 37%
lead. Solder with a greater tin content melts at a
lower temperature, takes less time to harden, and
generally makes it easier to do a good soldering job.
The ratio of tin is a main factor in the strength of the
solder joint. Solder with a greater tin content has a
greater holding ability under stress. Solder with a tin
ratio of 63% is the strongest, while solder with less
than 30% would be undesirable.

Safety Precautions

Like all electrical devices, the solder station must be
handled with care. The soldering iron and tip can
reach high temperatures and these simple safety
rules should be followed.

• Keep children out of reach of the soldering station.
yes, use safety goggles.

• To protect y

• Keep flammable material away from the soldering

iron.

• DO NO

water.

• Always assume that the tip is hot to avoid burns.

• Work in an area that is well ventilated.

• Be careful that the hot soldering iron tip or the

barrel of the iron does not come in contact with any

ical cord.

electr

• Do not hold solder in y

contains lead and is a to
hands thoroughly after handling solder.

• Locate soldering iron in an area where you do not

have to go around it or reach over it.

our e

T cool iron by dipping it into any liquid or

our mouth. Solder

xic substance

. Wash your

Flux

Most solder contains flux in the hollow core of the
solder allowing it to be applied automatically when
you heat the solder. The flux will remove any oxide
film on the metals soldered creating a good metal-to­metal contact. This is called “wetting the metal”.
There are three types of solder fluxes: chloride,
organic and rosin. In the electronics industry, only
the rosin type is used. Rosin flux comes in two types,
pure and active. The most reliable is the pure type,
since it doesn’t cause dendrites between tracks on
the PC board as the active type does. Due to the
highly corrosiv

e and moisture attracting
characteristics of the chloride and organic type
fluxes, they should not be used in electronics.

Surface Preparation

In order f
the metals must be clean and free of nonmetallic
materials. Flux in the solder can remove oxides from
metal but not other mater
remove these, use a small steel brush or fine emery
cloth.

or the solder to adhere to the connection,

ials like dirt or grease. To

Solder

Solder is a fusible alloy composed of tin and lead.
Some solder may contain small amounts of other
material for use in special purposes to enhance its
characteristics. Solder has a melting temperature
around 360

O

to 370O, making it ideal for forming a

metallic joint between two metals.

Solder

Rosin Core

Figure 1

Mechanical Connection

When all the surfaces are clean, the metals should
have a solid mechanical connection. Wires should
be tightly wrapped around each other or to the
terminal. This will eliminate large gaps that create

Solder should not be used as a

eak solder joints

w

.

mechanical connection.

Solder

Wire

erminal

T

Figure 2

-3-

Types of Soldering Devices

A

number of different types of soldering devices:

i

rons, guns and stations are available today. Irons
are used for light to medium work and guns are for
medium to heavy-duty work. The station type can
range from light to heavy-duty For working on PC
boards, irons ranging from 15 to 40 watts are
suitable, or a station with a range of 15 to 40 watts.
If you use an iron with a higher wattage rating than
40 watt, you may damage the copper tracks on the
PC board. The higher wattage irons are best suited
for heavy-duty electrical jobs.

Soldering Iron

Soldering Gun

Soldering Station

Solder Tips

The tip is the very important part of the iron. The
material that the tip is made from is an essential
factor. The soldering iron tip contains four different
metals as shown in Figure 3. The core consists of
copper. Since the copper is a soft material, it is
plated with iron. Chrome plating is used on the area
where no soldering tak
Then the tip is plated with tin, because it can be
easily cleaned.

es place to prevent oxidation.

Tip Cleaning

A

good clean solder tip makes soldering much

e

asier. The tip should be tinned by lightly coating it
with solder to prevent it from oxidizing. The tip can
become pitted (black spots) from normal use. It is
important to clean the tip by wiping it with a wet
sponge or rag. For tips that need a good cleaning,
the tip tinner and cleaner (#TTC1) should be used.

Ne

ver use a file or abrasive material to clean the

tip. Using such methods will damage the plating and

ruin the tip. Do not remove the excess solder from
the tip before storing. The excess solder will prevent
oxidation.

Clean Connections

Proper solder adhesion requires that the metal
surface to be free of dirt and grease. The flux only
removes the oxides so a brush or rag can be used to
clean metal. There are contact cleaners in aerosol
cans and other solvents available.

Desoldering

Great care should be taken when repairing or
correcting a mistake on a PC board. The metal foil
can be easily pulled up or broken from excessive
heat. Use the least amount of heat as possible. You
can use a desoldering tool, b
These tools will remove the solder enabling you to
correct the problem.

ulb, wick or a station.

Tin Plating

Chrome Plating

Iron Plating

Copper

Figure 3

Today, tips are manufactured in a variety of different
shapes (see figure below). The chisel shape is one
of the most common. Having a choice of tip styles
allows you to choose the one best suited for your
soldering needs. Due to the high heat, removable
tips can bond themselv
left in place f

or extended periods of time. Periodic

removal of the tip is therefore advisable.

1/32”

1/64”

es to the heating element if

1/16”

1/8”

3/64”

Desoldering Tool Desoldering Bulb

Solder

Wick

Desoldering Station

-4-

SOLDER PRACTICE

Double Pads

Before we begin to assemble and solder
the components to the solder practice
PC board, we will start first by practice
soldering to the double pads on the
edge of the PC board (see Figure 4).

1. Apply a small amount of solder to the iron tip. This
allows the heat to leave the iron and onto the foil.

2. Place the iron on the top half of pad and then
apply the solder (see Figure 5). Allow the solder
to flow around the pad. Then, remove the solder
and the iron and let the solder cool. The solder
should be neat and smooth.

3.

Repeat step 2 on the bottom half of the pad (see Fig. 5).

4. Practice again on the second large pad.

Solder

Soldering Iron

Figure 4

Tack Soldering

You will make 10 tack solder connections by
soldering five wires to the top row of pads.

1. Cut 5 one-inch wires and strip 1/8" insulation off
both ends.

2. Place the iron and the wire on top left pad as
shown in Figure 7. Allow the solder to flow around
the wire. Then, remove the iron and let the solder
cool. You may need to add some more solder.
The solder should be neat and smooth.

3.

Pull the wire to make sure you have a good solder joint.

4. Bend the wire and solder it to the next pad, as
shown in Figure 7.

5. Now solder the remaining wires to the pads as
shown in Figure 7.

Soldering Iron

Figure 5

Single Pads

Now practice using the single pads. Start with the four
square pads and use the same soldering procedures
as the large pads. Note that the spacing between the
pads decrease as the pads get smaller. Be sure there
are no solder br

idges betw

een the pads.

Solder Bridge

Solder bridges occur when solder runs between
circuit paths and creates a short circuit. This is
usually caused b
intentionally make a solder bridge on each section
(see Figure 6). Then, remove it by simply dragging
your soldering iron across the solder bridge as
shown. It is best to wipe the iron tip with a wet
sponge to remove the solder. You can also use
solder wic

k as descr

y using too much solder. Try to

ibed on page 7.

Solder

Figure 7

Jumper Wires

In this section, you will solder 20 jumpers between

ws of holes.

the tw

1. Cut a one-inch wire and str

2. Inser

3. Apply a small amount of solder to the tip.

4. Cut off the excess leads.

5. Solder the remaining 19 jumper wires.

o ro

ip 1/8" insulation off

both ends.

t the wire between the top and bottom hole

(see Figure 8a).

Immediately apply solder to the opposite side of
the connection, away from the iron. Allow the
heated wire and circuit foil to melt the solder (see
Figure 8b).

Figure 6

PC Board

Solder Bridges

ing Iron

Solder

Drag Iron

-5-

umper

J

Wires

Figure 8a

Solder

Figure 8b

Solder

Iron

ing

PC BOARD REPAIR

Hairline Cracks

The hairline cracks can develop in the copper foil if
the PC board is flexed. This can be easily repaired
by making a solder bridge across the two foils. The
solder should smoothly flow across the foil as shown
in Figure 9. If the solder does not adhere to the foil,
it will sit on the foil as a blob as shown if Figure 10.

Solder

Foil

Figure 9 Figure 10

1.

Make five solder bridges using the second row of
single pads, starting from the left side (see Figure 11).

Solder Bridges

Figure 11

Wide Gaps

Wide gaps in the copper foil can be bridged using a
small wire soldered across the gaps (see Figure 12).
Four wires will be soldered across the two rows of
small solder pads.

Board

Bare Wire

Solder

Foil

Figure 12

1. Place the iron on the top of a pad and then apply

the solder (see Figure 12). Allow the solder to
flow around and form a small pool.

2. Repeat Step 1 on the adjacent pad.

3. Strip 1/2" of insulation off one end of the wire and

then tin it.

4. Position the wire on top of the solder pad and then

place the iron on the wire. As the solder melts,
the wire will be pressed down against the pad

ve the iron while holding

(see Figure 12).
the wire in place. Make sure the wire does not
move until the solder hardens.

Remo

Reinforcing a Repair

A solder bridge repair can be reinforced using a solid
wire. Now add a wire to the five solder bridges you
just made.

1. Strip a 1/2" of insulation off one end of the wire
and then tin it.

2. Hold the tinned wire on top of the solder bridge.

3. Place the iron on the wire until the solder melts.

4. Remove the iron while holding the wire in place
against the foil. Make sure the wire does not
move until the solder hardens.

5. Check for a good solder connection.

6. Cut the wire off as close to the solder joint as
possib

7. Practice this procedure four more times.

le.

5. Check for a good solder connection.

6. Repeat step 4 on the adjacent pad.

7. Cut the wire off as close to the solder joint as
possible (see Figure 12).

8. You can hold the wire down with a screwdriver
and resolder if needed.

9. Practice this procedure three more times on the
remaining pads.

-6-

REMOVING EXCESS SOLDER USING DESOLDERING WICK

Desoldering wick is a braided wire coated with non­corrosive rosin flux. It is the simplest and safest tool
for removing solder from a solder connection. When
the braided wire is heated, the flux cleans and
breaks up the surface tension so the melted solder
from the connection flows into the braid by capillary
action.

Included in this kit is a six inch length of solder wick
(desoldering braid).

CAUTION: Wick gets HOT - use

Soldering Iron Tip

Foil Side of PC board

long nose pliers to hold wick.

Desoldering
Wick

Excess Solder

Using the Desoldering Wick

1. Place the wick against the solder with the tip of a
hot soldering iron (see Figure 13).

2. The molten solder is sucked up into the wick by
capillary action.

3. When the iron and wick are removed, the solder
should be removed. You need to repeat the
process if some solder remains.

If necessary, repeat the procedure until all of the
unwanted solder is removed.

After the excess solder has been removed, clip off
and discard the solder-saturated portion of the braid.
For best results, always use a fresh area of the braid
for each procedure.

A close-up view of the accumulation of solder onto

Using desoldering wick to remove excess solder.

Figure 13

the solder wic

k (desoldering br

Figure 14

aid).

RESISTOR READING EXERCISE

Before starting assembly of your solder practice project, you should be thoroughly familiar with the 4-band color
code system. Many of the resistor values will be identified by color bands and it is easy to mistake their value

ou read the colors incorrectly or read the value from the wrong end. Do the f

if y
values. Place your answer in the box beneath the resistor. Answers are on the bottom of this page.

(1) brown-green-red-gold

ellow-violet-bro

(5) y

wn-gold

(2) brown-black-orange-gold (3) brown-black-yellow-gold (4) red-red-orange-gold

y-orange-gold

(6) b

lue-gr

a

ellow-violet-b

(7) y

lack-gold

ollowing exercise in resistor

(8) bro

wn-blue-bro

wn-gold

(9) orange-orange-red-gold (10) green-brown-red-gold (11) brown-black-green-gold (12) brown-gray-orange-gold

-7-

5%; 7) 47Ω+5%; 8) 160Ω+5%; 9) 3.3kΩ+5%; 10) 5.1kΩ+5%; 11) 1MΩ+5%; 12) 18kΩ+5%

6) 68kΩ+

Answers to Resistor Reading Exercise: 1) 1.5kΩ+5%; 2) 10kΩ+5%; 3) 100kΩ+5%; 4) 22kΩ+5%; 5) 470Ω+5%;

THEORY OF OPERATION

The solder practice kit consists of a circuit oscillating
at one hertz (one cycle per second). The oscillator
consists of two transistors Q1 and Q2, and resistors,
R1 - R11 and capacitors C1 and C2. This
configuration is known as a multivibrator circuit.

When voltage is first applied to this multivibrator
circuit, one transistor (possibly Q1) will conduct
faster, causing transistor Q2 to stay off. Q1 will
continue to conduct until it saturates. At this point,

SCHEMATIC DIAGRAM

Q2 will start to conduct, causing Q1 to rapidly cutoff.
This process continues alternately causing Q1 or Q2
to conduct. The output will be a square wave. The
frequency is determined by the time constants of
resistor R6 and capacitor C1, also R12 and C2. Two
LED diodes are placed in the collectors of the
transistors and will light when current is passing
through them. Resistors R1 - R5, R7 -R11 determine
the current passing through the LEDs.

-8-

SOLDERING COMPONENTS TO THE PC BOARD

A poorly soldered joint can greatly affect small current flow in circuits and can cause equipment failure. You can damage
a PC board or a component with too much heat or cause a cold solder joint with insufficient heat. Sloppy soldering can
cause bridges between two adjacent foils preventing the circuit from functioning.

Safety Procedures

• Wear eye protection when soldering.

•

Locate soldering iron in an area where you do not have to go around it or reach over it.

• Do not hold solder in your mouth. Solder contains lead and is a toxic substance. Wash your hands thoroughly after

handling solder.

• Be sure that there is adequate ventilation present.

What Good Soldering Looks Like

A good solder connection should be bright, shiny,
smooth, and uniformly flowed over all surfaces.

Soldering a PC board

1. Solder all components from the copper foil side only.
Push the soldering iron tip against both the lead and
the circuit board foil.

Soldering Iron

Component Lead

Foil

Circuit Board

2. Apply a small amount of solder to the iron tip. This
allows the heat to leave the iron and onto the foil.
Immediately apply solder to the opposite side of the
connection, away from the iron. Allow the heated
component and the circuit foil to melt the solder.

Solder Soldering Iron

Foil

Types of Poor Soldering Connections

1. Insufficient heat - the solder will not flow onto the

lead as shown.

Rosin

Soldering iron positioned
incorrectly.

2. Insufficient solder - let the solder flow over the

connection until it is covered. Use just enough solder
to cover the connection.

Solder

Gap

Component Lead

3. Excessive solder - could make connections that you

did not intend to between adjacent foil areas or
terminals.

Solder

3. Allow the solder to flow around the connection. Then,
remove the solder and the iron and let the connection
cool. The solder should have flowed smoothly and not
lump around the wire lead.

Solder

Foil

Here is what a good solder connection looks like.

4.

Soldering Iron

Heat Sinking

Electronic components such as transistors
diodes can be damaged b
sinking is a wa
while solder
using long nose pliers
dissipating clip

y of reducing the heat on the components

ing. Dissipating the heat can be achieved by

, an alligator clip, or a special heat

. The heat sink should be held on the

y the heat dur

ing soldering. Heat

component lead between the part and the solder joint.

Soldering Iron

Heat Sink

(this can be ordered as par
Solder Ease Kit Model SE-1).

t of Elenco’

s

-9-

, IC’s, and

Solder

PC Board

Heat Sensitive
Component (Diode)

PC BOARD ASSEMBLY

Solder the following parts to the PC board.

J2 - Jumper Wire (see Fig. A)

J1 - Jumper Wire (see Fig. A)

J5 - Jumper Wire (see Fig. A)

J4 - Jumper Wire (see Fig. A)
R1 - 100Ω 5% ¼W Resistor

(brown-black-brown-gold)

(see Figure B)

R2 - 150Ω 5% ¼W Resistor

(brown-green-brown-gold)

(see Figure B)

R3 - 200Ω 5% ¼W Resistor

(red-black-brown-gold)

(see Figure B)

R4 - 220Ω 5% ¼W Resistor

(red-red-brown-gold)

(see Figure B)

Figure A

Cut a 1” wire and strip 1/8” of
insulation off of both ends.

J3 - Jumper Wire (see Fig. A)

J6 - Jumper Wire (see Fig. A)
R10 - 220Ω 5% ¼W Resistor

(red-red-brown-gold)

(see Figure B)

R9 - 200Ω 5% ¼W Resistor

(red-black-brown-gold)

(see Figure B)

R8 - 150Ω 5% ¼W Resistor

(brown-green-brown-gold)

(see Figure B)

R7 - 100Ω 5% ¼W Resistor

(brown-black-brown-gold)

(see Figure B)

Figure B

Mount the resistor flat against
the PC board as shown.

Resistance Testing #1 (If you do not have a meter, continue to page 11)

ou will test the solder connections by measuring the resistance from the following points. If your readings are

Y
different, double check your soldering connections.

Location Value Circuit

Point A (left side of J1) to point B (right side of J3) 0.1 - 1Ω (J1-J3)
Point A (left side of J1) to point C (top lead of R4) 670Ω

oint D (left side of J4) to point E (right side of J6) 0.1 - 1

P
Point D (left side of J4) to point F (top lead of R10) 670Ω

A

D

CF

+

5% (J1-J3, R1-R4)
+

Ω

5%

+

5% (J4-J6, R7-R10)

B

E

(J4-J6)

-10-

PC BOARD ASSEMBLY (continued)

Solder the following parts to the PC board.

U1 - 16-pin IC Socket

(see Figure C)

R14 - 27kΩ 5% ¼W Resistor

(red-violet-orange-gold)

(see Figure D)

R13 - 18kΩ 5% ¼W Resistor

(brown-gray-orange-gold)

(see Figure D)

R17 - 100kΩ 5% ¼W Resistor

(brown-black-yellow-gold)

(see Figure D)

R18 - 120kΩ 5% ¼W Resistor

(brown-red-yellow-gold)

(see Figure D)

Figure C

R15 - 39kΩ 5% ¼W Resistor

(orange-white-orange-gold)

(see Figure D)

R16 - 47kΩ 5% ¼W Resistor
(yellow-violet-orange-gold)

(see Figure D)

R19 - 470kΩ 5% ¼W Resistor

(yellow-violet-yellow-gold)

(see Figure D)

R20 - 680kΩ 5% ¼W Resistor

(blue-gray-yellow-gold)

(see Figure D)

Figure D

Notch

When mounting the IC socket,
make sure that the notch is in the
same direction as marked on the
PC board.

Stand resistor on end as
shown with the body
inside the white circle

White Circle

Resistance Testing #2 (If you do not have a meter, continue to page 12)

Each resistor is connected across two pins of the IC socket. You will test the solder connections by measuring
the resistance from the following IC pins. If your readings are different, double check your soldering connections.

Location Value

R14 - Measure from pin 1 to pin 2
R13 - Measure from pin 3 to pin 4 18kΩ +/– 5%
R17 - Measure from pin 5 to pin 6
R18 - Measure from pin 7 to pin 8 100kΩ +/– 5%
R19 - Measure from pin 9 to pin 10
R20 - Measure from pin 11 to pin 12 680kΩ +/– 5%

27k

Ω +/– 5%

120kΩ +/– 5%

470k

Ω +/– 5%

1

16

R16 - Measure from pin 13 to pin 14
R15 - Measure from pin 15 to pin 16 39kΩ +/– 5%

-11

47k

Ω +/– 5%

8

9

PC BOARD ASSEMBLY (continued)

Solder the following parts to the PC board.

R6 - 56kΩ 5% ¼W Resistor

(green-blue-orange-gold)

(see Figure B)

R5 - 330Ω 5% ¼W Resistor

(orange-orange-brown-gold)

(see Figure B)

C1 - 10µF 16V Electrolytic

(see Figure E)

Battery Snap (see Figure F)

SW1 - Switch SPST

LED1 - Red LED

(see Figure G)

Q1 - 2N3904 Transistor

(see Figure H)

Figure E

Electrolytic capacitors have
polarity. Be sure to mount them
with the negative (–) lead
(marked on side) in the correct
hole.

Polarity

Mark

Figure F

Thread the battery snap wires through the hole
in the PC board from the solder side as shown.
Solder the red wire to the (+) point and the
black wire to the (–) point on the PC board.

Red

Black

R12 - 56kΩ 5% ¼W Resistor

(green-blue-orange-gold)

(see Figure B)

R11 - 330Ω 5% ¼W Resistor

(orange-orange-brown-gold)

(see Figure B)

C2 - 10µF 16V Electrolytic

(see Figure E)

LED2 - Red LED

(see Figure G)

Q2 - 2N3904 Transistor

(see Figure H)

J7 - Jumper Wire

(see Figure A)

Figure G

Mount the LED onto the PC board with
the flat side of the LED in the same
direction as marked on the PC board.

Mount flush

with PC board

Flat

(–) (+)

Figure H

Mount the IC with the flat side in the
same direction as marked on the PC

Solder and cut off the excess

board.
leads.

Flat

OPERATION

Connect a 9 volt battery to the battery snap. Turn the ON/OFF switch to the ON position and the LEDs should
alternately light.

-12-

TROUBLESHOOTING

If you are a student, and any parts are missing or
damaged, please see instructor or bookstore. If you
purchased this solder practice kit from a distributor,
catalog, etc., please contact Elenco
(address/phone/e-mail is at the back of this manual)
for additional assistance, if needed.

If you are experiencing a problem, first read the
theory of operation to familiarize yourself with the
operation.

Component Check

1. Be sure that all components have been mounted

in their correct places.

®

Electronics

4. Pay close attention to the red and black wires of
the battery snap. The red wire should be installed
in the positive (+) hole and the black wire in the
negative (–) hole. Snap in a fresh 9-volt battery.

Problems

1. No LEDs Light

• Check the solder connections for the battery
wires and switch.

• Check that all parts are in the correct way.

2. LED1 Does Not Light

• Check C1, LED1 and Q1.

2. Make sure that C1 and C2, the electrolytic
capacitor is mounted correctly. The negative lead
should be in the hole as shown on the top legend.

3. Have LEDs LED1 and LED2 been installed
correctly? The flat side of their bodies should be
in the same direction as marked on the top
legend. If the LEDs are in bac
light.

kwards, they will not

3. LED2 Does Not Light

• Check C2, LED2 and Q2.

4. LED1 or LED2 is Always On

• Check C1 and C2 for opens.

• Check Q1 and Q2 for shorts.

WORD GLOSSARY

Capacitor An electr

time.

Cold Solder Joint Occurs because insufficient heat w

the solder had set. Connection looks crystalline, crumbly, or dull.

Flux

Heat Sinking A process of keeping the component from becoming overheated during soldering.

A substance that is used to cleanse the surf
used in electronics work. Most of the solder used in electronics has flux built right into it.

y metal object that can be clamped to the component lead will work as an effective

An
heat sink.

ical component that can store electrical pressure (v

as applied or the connection was mo

ace of oxide before it is soldered.

An alligator clip or pliers work well.

oltage) f

or periods of

ved before

Always

Integrated Circuit (IC) A type of circuit in which transistors, diodes, resistors, and capacitors are all

constructed on a semiconductor base.

umper

J

LED Common abbreviation for light emitting diode.
Light Emitting Diode A diode made from gallium arsenide that has a tur

Oxidation Most metals, when exposed to air, form an oxide on their surface which prevents

olarity

P
Printed Circuit Board A board used for mounting electrical components.

Wire

A wire that is connected from one place to another on a PC board, thereb
connection betw

generated when current flows through it.

solder from adhering to the metal.
The division of tw

Components are connected using metal traces “printed” on the board instead of
wires.

een two pads.

o opposing f

-13-

orces or proper

ties

y making a

n-on energy so high that light is

.

WORD GLOSSARY (continued)

Resistor Component used to control the flow of electricity in a circuit. It is made of carbon.
Rosin Core Solder The most common type of solder used in electronics generally referred to as 63/37

rosin core solder.

Solder A tin/lead alloy that melts at a very low temperature, used to join other metals

together. It produces excellent electrical connections.

Solder Bridge An unwanted solder connection between two points that are close together.
Solder Melting Point The temperature at which a tin/lead alloy (solder) melts. The common solder used in

electronics (63% tin / 37% lead) has a melting point of 361

O

F.

Solder Wick Braided wire coated with flux to effectively remove solder from a connection.
Soldering The process of joining two or more metals by applying solder to them.
Tack Soldering A connection where the lead or wire does not have any mechanical support.
Tinning the Tip A process of coating the soldering iron tip with solder to minimize the formation of

oxide on the tip, which would reduce the amount of heat transfer.

Transistor An electronic device that uses a small amount of current to control a large amount of

current.

Wire Gauge Refers to the size of the wire. The bigger the number, the smaller the diameter of the

wire. 18 gauge to 24 gauge is generally used for hook-up in electronics.

QUIZ

1. Solder is comprised of what two materials?

r A. Gold and copper
r B. Tin and lead
r C. Zinc and copper
r D. Lead and aluminum

2. What type of flux should be used in electronics?

r A. Chloride
r B. Organic
r C. Rosin
r D. Corrosive

6. Solder wick is used to . . .

r A. remove solder.
r B. solder in small parts.
r C. cleaning the soldering iron tip.
r D. removing flux.

7. A cold solder joint is caused by . . .

r A. a solder bridge.
r B. using 60/40 solder.
r C. insufficient heat.
r D. acid core solder.

3. When working on PC boards, what wattage range of iron

is ideal?

r A. 15-40 watts
r B. 50-100 watts
r C. 1-10 watts
r D. 100-200 watts

4. Tinning the soldering tip will prevent it from . . .

r A. heating.
r B. melting.
r C. soldering.
r D. oxidizing.

5. Proper solder adhesion requires that the metal surface

to be . . .

r A. solder free.

clean.

.

r B
r C. greasy.
r D. cold.

8. When two adjacent solder joints accidentally touch, it is
called . . .

r A. a jumper.
r B. a blob.
r C. a solder hole.
r D. a solder bridge.

9. What ratio has the greatest amount of tin?

r A. 20/60
r B. 40/60
r C. 50/50
r D. 63/37

10. A good solder connection should be . . .

r A. dull and rough.

ight and smooth.

, br

y

shin

.

r B
r C. lumped around the connection.
r D. soldered on one side of the connection.

Ans

s:

wer

1.

B

, 2.

C

, 3. A, 4. D, 5. B, 6. A, 7. C, 8. D, 9. D, 10. B

-14-

Elenco®Electronics, Inc.

150 Carpenter Avenue

Wheeling, IL 60090

[phone]

Website: www.elenco.com

e-mail: [e-mail]