TRANSISTOR - DIODE TESTER KIT
MODEL DT-100K
Assembly and Instruction Manual
Copyright © 2014, 1988 by ELENCO®All rights reserved. Revised 2014 REV-R 753110
No part of this book shall be reproduced by any means; electronic, photocopying, or otherwise without written permission from the publisher.
ELENCO
®
-1-
Qty. Description Part #
! 1 PC board 511100
! 1 Switch push button 540001
with 1/4” nut and washer
! 2 Switch DPDT 541111
! 1 Battery snap 590098
! 1 Battery clip 590099
! 1 Knob 622009
! 1 Case top 623061
! 1 Case bottom 623062
! 5 Spacer LED 624111
! 4 Screw M3 x 0.5 x 5mm 640300
! 4 Screw 2.8 x 8mm 641102
! 1 7mm Hex pot nut 644101
! 1 8mm x 14mm Washer 645101
! 1 Lockwasher 5/16” 646101
Qty. Description Part #
! 4 Rubber feet 662015
! 1 Socket 8-Pin IC 664008
! 1 Transistor socket 664500
! 1 Alligator clip black 680001
! 1 Alligator clip red 680002
! 1 Alligator clip green 680003
! 1 Alligator clip yellow 680004
! 1 Label top panel 723070
! 4” Double-sided tape 740020
! 1 Wire black 15” 813110
! 1 Wire red 15” 813210
! 1 Wire yellow 15” 813410
! 1 Wire green 15” 813510
! 1 Wire blue 3” 814620
! 1 Solder tube lead-free 9LF99
DT-100 PARTS LIST
If you are a student, and any parts are missing or damaged, please see instructor or bookstore.
If you purchased this transistor–diode tester 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. DO NOT contact your
place of purchase as they will not be able to help you.
RESISTORS
Qty. Symbol Value Color Code Part #
! 1 R14 100Ω 5% 1/4W brown-black-brown-gold 131000
! 2 R5, R6 220Ω 5% 1/4W red-red-brown-gold 132200
! 2 R1, R10 330Ω 5% 1/4W orange-orange-brown-gold 133300
! 1 R13 1kΩ 5% 1/4W brown-black-red-gold 141000
! 1 R7 5.6kΩ 5% 1/4W green-blue-red-gold 145600
! 1 R12 10kΩ 5% 1/4W brown-black-orange-gold 151000
! 1 R8 18kΩ 5% 1/4W brown-gray-orange-gold 151800
! 2 R2, R3 33kΩ 5% 1/4W orange-orange-orange-gold 153300
! 1 R9 47kΩ 5% 1/4W yellow-violet-orange-gold 154700
! 1 R11 100kΩ 5% 1/4W brown-black-yellow-gold 161000
! 1 R4 330kΩ 5% 1/4W orange-orange-yellow-gold 163300
! 1 R15 100kΩ 5% 1/4W Potentiometer 192611
CAPACITORS
Qty. Symbol Value Description Part #
! 1 C6 .001µF (102) Discap 231036
! 3 C2, C3, C5 .01µF (103) Discap 241031
! 2 C1, C4 10µF Electrolytic 271045
SEMICONDUCTORS
Qty. Symbol Value Description Part #
! 1 D1 1N4001 Diode 314001
! 1 Q5 MPS A70 Transistor 320070
! 4 Q1-Q4 2N3904 Transistor 323904
! 1 IC1 555 Integrated circuit (IC) 330555
! 5 L1-L5 Light emitting diode (LED) 350002
MISCELLANEOUS
-2-
PARTS VERIFICATION
Before beginning the assembly process, familiarize yourself with the components and this instruction book.
Verify that all of the parts are present. This is best done by checking off the parts in the parts list.
RESISTORS CAPACITOR SEMICONDUCTORS
Electrolytic
(radial)
Diode
100kΩ Potentiometer Transistor LED
Knob
MISCELLANEOUS
Switch DPDT
PC Board
Case top
Case bottom
Screws
2.8 x 8mm
M3 x 0.5 x 5mm
7mm
Nuts Washers
Flat
8 x 14mm
Lockwasher 5/16”
Rubber foot
Spacer LED
Label
Lead-free solder
Carbon film
8-pin Socket555 ICDiscap
Battery snap
Transistor
socket
Push button switch with
1/4” nut and washer
Alligator clip
Wires
Double-sided tape
Battery clip
-3-
CONSTRUCTION
Solder
Soldering Iron
Foil
Solder
Soldering Iron
Foil
Component Lead
Soldering Iron
Circuit Board
Foil
Rosin
Soldering iron positioned
incorrectly.
Solder
Gap
Component Lead
Solder
Soldering Iron
Drag
Foil
1. Solder all components from the
copper foil side only. Push the
soldering iron tip against both the
lead and the circuit board foil.
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.
1. Insufficient heat - the solder will
not flow onto the lead as shown.
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.
4.
Here is what a good solder
connection looks like.
2. Insufficient solder - let the
solder flow over the connection
until it is covered.
Use just enough solder to cover
the connection.
3. Excessive solder - could make
connections that you did not
intend to between adjacent foil
areas or terminals.
4. Solder bridges - occur when
solder runs between circuit paths
and creates a short circuit. This is
usually caused by using too
much solder.
To correct this, simply drag your
soldering iron across the solder
bridge as shown.
What Good Soldering Looks Like
A good solder connection should be bright, shiny, smooth, and uniformly
flowed over all surfaces.
Types of Poor Soldering Connections
Introduction
The most important factor in assembling your DT-100K Transistor Diode Kit is good soldering techniques. Using the proper soldering iron
is of prime importance. A small pencil type soldering iron of 25 watts is
recommended. The tip of the iron must be kept clean at all times
and well-tinned.
Solder
For many years leaded solder was the most common type of solder
used by the electronics industry, but it is now being replaced by leadfree solder for health reasons. This kit contains lead-free solder, which
contains 99.3% tin, 0.7% copper, and has a rosin-flux core.
Lead-free solder is different from lead solder: It has a higher melting
point than lead solder, so you need higher temperature for the solder to
flow properly. Recommended tip temperature is approximately 700OF;
higher temperatures improve solder flow but accelerate tip decay. An
increase in soldering time may be required to achieve good results.
Soldering iron tips wear out faster since lead-free solders are more
corrosive and the higher soldering temperatures accelerate corrosion,
so proper tip care is important. The solder joint finish will look slightly
duller with lead-free solders.
Use these procedures to increase the life of your soldering iron tip when
using lead-free solder:
• Keep the iron tinned at all times.
• Use the correct tip size for best heat transfer. The conical tip is the
most commonly used.
• Turn off iron when not in use or reduce temperature setting when
using a soldering station.
•
Tips should be cleaned frequently to remove oxidation before it becomes
impossible to remove. Use Dry Tip Cleaner (Elenco®#SH-1025) or Tip
Cleaner (Elenco®#TTC1). If you use a sponge to clean your tip, then use
distilled water (tap water has impurities that accelerate corrosion).
Safety Procedures
• Always wear safety glasses or safety goggles to
protect your eyes when working with tools or
soldering iron, and during all phases of testing.
• Be sure there is adequate ventilation when soldering.
•
Locate soldering iron in an area where you do not have to go around
it or reach over it. Keep it in a safe area away from the reach of
children.
• Do not hold solder in your mouth. Solder is a toxic substance.
Wash hands thoroughly after handling solder.
Assemble Components
In all of the following assembly steps, the components must be installed
on the top side of the PC board unless otherwise indicated. The top
legend shows where each component goes. The leads pass through the
corresponding holes in the board and are soldered on the foil side.
Use only rosin core solder.
DO NOT USE ACID CORE SOLDER!
ASSEMBLE THE FOLLOWING COMPONENTS TO THE PC BOARD
R4 - 330kΩ Resistor
(org-org-yel-gold)
R1 - 330Ω Resistor
(org-org-brn-gold)
R3 - 33kΩ Resistor
R2 - 33kΩ Resistor
(org-org-org-gold)
R13 - 1kΩ Resistor
(brn-blk-red-gold)
R12 - 10kΩ Resistor
(brn-blk-org-gold)
R11 - 100kΩ Resistor
(brn-blk-yel-gold)
R14 - 100Ω Resistor
(brn-blk-brn-gold)
J1 - Jumper Wire
(see Figure A)
R5 - 220Ω Resistor
R6 - 220Ω Resistor
(red-red-brn-gold)
R9 - 47kΩ Resistor
(yel-vio-org-gold)
R8 - 18kΩ Resistor
(brn-gray-org-gold)
R7 - 5.6kΩ Resistor
(grn-blue-red-gold)
R10 - 330Ω Resistor
(org-org-brn-gold)
SAVE 3 CUT-OFF
RESISTOR LEADS
Figure D
Mount with the flat side of
LED as shown in the top
legend of the PC board.
Figure E
Figure F
Figure A
Form jumper wire from a
discarded resistor lead.
Figure B Figure C
Mount with the flat side of the
transistor as shown on the top
legend of the PC board. Leave 1/8”
between the part and PC board.
Be sure that the positive lead is in the correct
hole as shown on the PC board. Bend the
electrolytic over and solder into place.
Warning: If the capacitor is connected with
incorrect polarity, it may heat up and either leak
or cause the capacitor to explode.
Insert the IC socket
into the PC board
with the notch in the
direction shown on
the top legend.
Solder the IC
socket into place.
Insert the IC into
the socket with the
notch in the same
direction as the
notch on the socket.
Diodes have polarity, so be sure that the band is
in the correct direction, as shown on the top
legend of the PC board.
Notch
Flat
Spacer
Jumper wire
Polarity mark
Band
D1
-4-
Flat PC board
marking
Flat
Flat PC board marking
The positive (+) lead is
Marking on legend
side of PC board
Bend 90°
1/8”
-5-
ASSEMBLE THE FOLLOWING COMPONENTS TO THE PC BOARD
Q1 - 2N3904 Transistor
(see Figure B)
C1 - 10µF Electrolytic
(see Figure C)
Q5 - MPS A70 Transistor
(see Figure B)
C3 - .01µF Discap
C2 - .01µF Discap
(may be marked 103)
Q2 - 2N3904 Transistor
Q3 - 2N3904 Transistor
(see Figure B)
C6 - .001µF Discap
(may be marked 102)
C5 - .01µF Discap
(may be marked 103)
L1 - LED & Spacer
L4 - LED & Spacer
L2 - LED & Spacer
L5 - LED & Spacer
L3 - LED & Spacer
(see Figure D)
Q4 - 2N3904 Transistor
(see Figure B)
C4 - 10µF Electrolytic
(see Figure C)
8-Pin IC Socket
IC1 - 555 IC
(see Figure E)
D1 - 1N4001 Diode
(see Figure F)
SW2 - Switch DPDT
R15 - 100kΩ
potentiometer
5/16” Lockwasher
7mm Hex pot nut
8mm x 14mm Washer
(see Figure G)
S1 - Transistor socket
(see Figure H)
SW1 - Switch DPDT
Figure G Figure H
Cut off the mounting tab on the potentiometer (pot). Place a 5/16” lockwasher
onto the shaft of the pot. Insert the shaft of the pot into the hole in the PC
board from the copper side. Position the pot so that the three lugs are above
the three copper pads on the PC board. Secure the pot to the PC board with
the 7mm pot nut and 8mm flat washer. Solder a bare wire (discarded resistor
lead) from the pot lug to the pad directly below on all three lugs.
Bare wire
Pad
Match key on the socket to the top
legend marking on the PC board.
Mount with 1/16” of space between
the socket and PC board.
Key
Cut off tab
To p l eg e nd
marking
1/16”
Green copper side
of PC board
-6-
FINAL ASSEMBLY
! Peel the backing off of the front label and carefully
adhere it to the top case, aligning the holes while
doing so, as shown in Figure I.
! Install the push button switch to the top case in
the hole marked “TEST” as shown Figure J.
Fasten switch in place with the ¼” nut and
washer. Tighten the nut with pliers.
! Strip ¼” insulation off both ends of the red wire.
Insert one end into the hole marked “DIODE” on
the blue legend side of the PC board and solder
the wire into place. Tie a knot 2 ½” from the
soldered end of wire. Pull the free
end through the hole of the top case
marked “DIODE”, see Figure K.
! Strip ¼” insulation off both ends of
the black wire and insert one end
into hole “E” on the blue legend side
of the PC board and solder the wire
into place. Tie a knot 2 ½” from the
soldered end of the wire. Pull the
free end through the hole of the top
case marked “E”, see Figure K.
! Strip ¼” insulation off both ends of the yellow wire
and insert one end into hole “B” on the blue
legend side of the PC board and solder the wire
into place. Tie a knot 2 ½” from the soldered end
of the wire. Pull the free end through the hole of
the top case marked “B”, see Figure K.
! Strip ¼” insulation off both ends of the green wire
and insert one end into hole “C” on the blue
legend side of the PC board and solder wire into
place. Tie a knot 2 ½” from the soldered end of
wire. Pull the free end through the hole of the top
case marked “C”, see Figure K.
Figure K
Figure J
Figure I
Red wire
Green wire
Yellow wire
Black wire
Knots
Push button switch
Washer
¼” Nut
Top case
-7-
! Strip the insulation off both ends of the blue wire
to expose 1/4” of bare wire. Solder one end to the
hole on the copper side of the PC board, as
shown in Figure L. Solder the other end of the
wire to a lug on the push button switch.
! Solder the red wire from the battery snap to the
other lug on the push button switch, as shown in
Figure L.
! Insert the black wire from the battery snap into the
pad on the PC board from the copper side. Solder
the wire in place, as shown in Figure L.
Figure L
!
Mount the front panel to the switches on the PC
board using four M3 x 0.5 x 5mm screws (see
Figure M).
Figure M
M3 x 0.5 x 5mm ScrewsM3 x 0.5 x 5mm Screws
Blue wire
Push button switch
Battery snap
Black wire
Red wire
-8-
! Remove the colored boots from the four alligator
clips (to remove the boots, clip the alligator clip
onto a pencil and slide the boot off). Slide each
boot onto the four corresponding colored wires
(black boot onto black wire, etc.).
! Solder an alligator clip to each wire as shown in
Figure N. Slide the boots back onto the clips.
! Turn the shaft of the base current control fully
counter-clockwise. Align the marker line on the
knob with “0” on the front panel, see Figure O.
Push the knob onto the shaft.
! Peel off one side of the protective backing on the
double-sided tape and attach it to the battery clip.
Now, peel off the other side and attach the clip to
the case as shown in Figure P.
! Obtain a 9 volt battery (alkaline preferred) and
press the battery snap onto the battery terminals.
! Insert the battery into the battery clip.
! Remove the backing from each rubber foot and
place them in the locations shown in Figure Q.
! Assemble the top and bottom case sections and
fasten with four 2.8 x 8mm self-tapping screws as
shown in Figure Q. Make sure the slots on the
side line up with one another.
Your transistor/diode tester is now completed and
ready for testing.
Figure N
Clip
Bend tabs
over wire
Boot
Solder
Figure O
Knob
Line on
knob
Flat head
screwdriver
blade
Pot shaft
Figure P
Figure Q
Ta pe
9V Battery
2.8 x 8mm Screws
2.8 x 8mm
Screws
Rubber feet
Rubber
feet
Slot
Battery
clip
-9-
CHECKING OUT YOUR TRANSISTOR/DIODE TESTER
The following is a simple procedure for testing your DT-100. If the tests fail, refer to the troubleshooting guide
for help.
Diode Operation:
1. Place the switch in the diode position. Short the
black and red leads together and push in the test
button. The diode test LEDs should alternately go
on at about a 1Hz rate.
2. Connect the red and black leads to any good
diode. Only one LED should flash identifying the
red lead connection (anode or cathode).
Reversing the leads should cause the other LED
to flash.
Transistor Operation:
(using leads)
1. Place the switch in transistor position. Short the
yellow (B) and black (E) leads together. Press the
test button. Vary the base current control. The
NPN lamp should light with the switch in NPN and
the PNP when in PNP position.
(using socket)
2. Place a known good transistor in the test socket
with the Emitter in E, Base in B and Collector in C
pins. Be sure none of the leads are shorting. Vary
the base current control. The OK LED should
light. Note that on NPN transistor, the NPN lamp
also will glow very slightly. This indicates the base
current. The higher the beta of the transistor, the
lower the base current, and thus, lower intensity.
The base current control should be adjusted for
the lowest setting with the OK lamp glowing.
OPERATING INSTRUCTIONS
The DT-100 is a dynamic transistor and diode tester. It features in-circuit testing and polarity indicators for both
transistors and diodes.
Diode Testing
1. Place switch in diode position.
2. Connect diode to red and black leads.
3. Push in test switch. One diode LED should blink
and identify whether the cathode or anode is
connected to the diode (red) lead.
4. If both LED lamps blink, then the diode is shorted.
5. If neither lights, then the diode is open.
Transistor Testing
The DT-100 can measure transistors in or out of
circuit. It will identify NPN or PNP by a simple
adjustment.
Transistor testing - Out of Circuit
1. Place switch in transistor position.
2.
Place transistor in socket or attach to C, B, E
leads. If collector C, base B and emitter E are not
known, assume B is the center lead on small
plastic transistors and C the metal case or tab on
power transistors.
3.
Push in test button. Adjust the base current control
so that OK LED lights. This indicates a good
transistor.
4. If OK lamp does not light, then adjust the base
current control that either NPN or PNP LED lights.
This happens at minimum or maximum position of
the control setting. This will indicate transistor
type. Place switch to NPN if the NPN lamp lights,
to PNP if PNP lamp is lit.
5. If no lamps light, the transistor is open or we have
not identified the base lead. Repeat assuming
another lead as base.
6. When the transistor is shown to be OK, the base
current control gives an indication of transistor
beta. The lower the setting relative to another
transistor, the higher the beta. Lamps NPN and
PNP measure base current. Higher base current
results in a brighter LED. It also indicates if
current is entering or leaving the base, thus NPN
or PNP respectively will light.
Transistor Testing - In Circuit
The DT-100 will test transistors in circuit provided the
base biasing resistance is greater than 100 ohms.
Simply follow the previous procedure for testing out
of circuit transistors. Do not apply power to circuit of
transistor or diode under test. The DT-100 will supply
the necessary power.
-10-
Note the schematic diagram on the back cover of
this manual. The test transistor in this circuit is a
NPN. Adjusting the variable resistor will cause the
NPN LED to light, indicating that base current is
flowing. The output of the test transistor is fed to
amplifier Q2 and Q3. The output of Q2 is fed back in
phase to the base of the test transistor causing the
circuit to oscillate. Part of the oscillations are fed to a
power rectifier Q5 which switches on the OK LED
indicator.
The design configuration is such that in-circuit
transistors can be measured provided that the base
and collector resistors are greater than 100 ohms.
When measuring PNP transistors, the power
supplied to the test transistor is reversed via the
NPN/PNP switch, therefore the PNP LED will light.
Varying the base current control will reduce the base
current. The lower the base current, the higher the
gain of the transistor under test. Comparative tests
of two transistors gain (beta) can be made by
observing the dial setting or the intensity of the base
LED diode. The lower the setting with the PNP LED
lit, the higher the beta of that transistor.
On diode operation, power is applied to IC1. This
causes the circuit to oscillate at about a 1Hz rate.
Placing a diode in series with the LED indicators will
cause a current to flow depending on the direction of
the diode. Thus, the red test lead will identify the
cathode or anode of the diode via the LED readout.
Transistor Q4 reverses the current flow in this circuit.
All types of diodes may be tested: Silicon,
germanium, LEDs or zeners over 6 volts. Zener
diodes under 6V causes the second LED to glow at
lower intensity, indicating that zener breakdown has
occurred.
THEORY OF OPERATION
If any problems occur, first check your wiring and
soldering. Keep in mind that most problems are due
to poor soldering or wiring errors. Be sure that there
are no solder shorts, poor connections or wiring
errors. Check that the battery is connected. Be sure
that the transistors are in correctly. Check the LEDs.
The LED leads are hard to identify and can easily be
wired backwards. The following is a guide to help
solve most problems.
Diode Position:
Red and black leads shorted
together. LEDs should alternately blink at 1Hz rate.
A. LEDs do not blink. Check that IC1 is in
correctly. Check wiring around IC1.
B. Only one LED blinks. Check for open LED.
Check transistor Q4.
C. Both LEDs blink together. One LED is in
backwards.
Transistor Position Using Leads: B&E test leads
shorted together. Rotate base current from minimum
to maximum. NPN LED should light up when
switched to NPN and PNP LED should light when in
PNP position. OK LED should not light.
A. No LEDs light. Check that the battery is
connected properly. Check for open circuit at
R15, B or E leads.
B. Only one LED lights. Check wiring and
soldering. Check for open LED.
C. Both LEDs light at the same time. LED is in
backwards.
Transistor Position Using Socket: Put the good
NPN transistor into the test socket. Switch SW1 to
NPN position. Rotate base current control. The OK
lamp should light. If not, check the following:
A. No test leads are shorting together.
B. The NPN LED should be lit. If not, then refer to I.
C. Components around transistors Q1 to Q5 are in
properly. Be sure no soldering errors exist.
D. Transistors are not in backwards.
E. Touch the collector of Q1 with the black (E) test
leads. The OK LED should light. If not, then the
LED is either open or in backwards.
F. Look for a possible defective transistor or other
component.
TROUBLESHOOTING GUIDE
ELENCO
®
150 Carpenter Avenue • Wheeling, IL 60090
(847) 541-3800 • www.elenco.com • e-mail: elenco@elenco.com
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