Peak Atlas DCA55 User manual

Atlas DCA55
Semiconductor Component Analyser
Model DCA55 (Firmware: 4.1)
Designed and manu actured with pride in the UK
User Guide
© Peak Electronic Design Limited 2000/2021
In the interests o development, in ormation in this guide is subject to change without notice.
E&OE
EN55-14

DCA55 User Guide November 2021 – Rev 14
Page 2
Want to use it now?
We understand that you want to use your DCA55 right now. The unit
is ready to go and you should have little need to refer to this user
guide, but please make sure that you do at least take a look at the
notices on page 4!
Contents Page
Introduction ................................................................................... 3
Important onsiderations .............................................................. 4
Analysing semiconductors ............................................................. 5
Diodes ..................................................................................... 7
Diode Networks ...................................................................... 8
LEDs ....................................................................................... 9
Bicolour LEDs ...................................................................... 10
Bipolar Junction Transistors (BJTs) ...................................... 11
Digital Transistors ................................................................. 18
Enhancement Mode MOSFETs ............................................. 19
Depletion Mode MOSFETs................................................... 20
Junction FETs (JFETs) .......................................................... 21
Thyristors (S Rs) and Triacs ................................................ 22
Taking care of your D A55 ........................................................ 23
Battery replacement .............................................................. 23
Self Tests ............................................................................... 24
Appendix A - Technical Specifications ....................................... 25
Appendix B - Statutory Information ............................................ 28
This user guide has been written to accompany the DCA55 with revision 4.1
firmware. Other revisions of firmware may differ in operation, features and
specifications. The firmware version is displayed briefly upon power-up.

DCA55 User Guide November 2021 – Rev 14
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Introduction
The Peak Atlas DCA55 is an intelligent semiconductor analyser that offers
great features together with refreshing simplicity. The DCA55 brings a world
of component data to your fingertips.
Summary Features:
 Automatic component type identification
 Bipolar transistors
 Darlington transistors
 Enhancement Mode MOSFETs
 Depletion Mode MOSFETs
 Junction FETs
 Low power sensitive Triacs
 Low power sensitive Thyristors
 Light Emitting Diodes
 Bicolour LEDs
 Diodes
 Diode networks
 Automatic pinout identification, just connect any way round.
(only the gate is identified on JFETs)
 Special feature identification such as diode protection and resistor
shunts.
 Gain measurement for bipolar transistors.
 Leakage current measurement for bipolar transistors.
 Silicon and Germanium detection for bipolar transistors.
 Gate threshold measurement for Enhancement Mode MOSFETs.
 Semiconductor forward voltage measurement for diodes, LEDs and
transistor Base-Emitter junctions.
 Automatic and manual power-off.

DCA55 User Guide November 2021 – Rev 14
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Important Considerations
Please observe the following guidelines:
 This instrument must NEVER be connected to powered
equipment/components or equipment/components with any
stored energy (e.g. charged capacitors). Failure to comply
with this warning may result in personal injury, damage to
the equipment under test, damage to the DCA55 and
invalidation of the manufacturer’s warranty.
 The DCA55 is designed to analyse semiconductors that are
not in-circuit, otherwise complex circuit effects will result
in erroneous measurements.
 Avoid rough treatment or hard knocks.
 This unit is not waterproof.
 Only use a good quality battery (details on page 23).

DCA55 User Guide November 2021 – Rev 14
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Analysing Components
The DCA55 is designed to analyse discrete,
unconnected, unpowered components. This ensures
that external connections don’t influence the measured
parameters. The three test probes can be connected to the
component any way round. If the component has only two terminals,
then any pair of the three test probes can be used.
The DCA55 will start component
analysis when the on-test button is
pressed.
Depending on the component type, analysis may take a few seconds to
complete, after which, the results of the analysis are displayed. Information is
displayed a “page” at a time, each page can be displayed by briefly pressing
the scroll-off button.
The arrow symbol on the display indicates that more pages are available
to be viewed.
 Although the DCA55 will switch itself off if left unattended, you can
manually switch the unit off by holding down the scroll-off button
for a couple of seconds.
Peak Atlas DCA
model DCA55 Rx.x

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If the DCA55 cannot detect any
component between any of the test
probes, the following message will be
displayed:
If the component is not a supported
component type, a faulty component or
a component that is being tested in-
circuit, the analysis may result in the
following message being displayed:
Some components may be faulty due to
a shorted junction between a pair of the
probes. If this is the case, the following
message (or similar) will be displayed:
If all three probes are shorted (or very
low resistance) then the following
message will be displayed:
 It is possible that the DCA55 may detect one or more diode junctions
or other component type within an unknown or faulty part. This is
because many semiconductors comprise of PN (diode) junctions.
Please refer to the section on diodes and diode networks for more
information.
No component
detected
Unknown/Faulty
component
Short c rcu t on
Green Blue
Short c rcu t on
Red Green Blue

DCA55 User Guide November 2021 – Rev 14
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Diodes
The DCA55 will analyse almost any type of diode. Any
pair of the three test clips can be connected to the diode, any way
round. If the unit detects a single diode, the following message will be
displayed:
Pressing the scroll-off button will then
display the pinout for the diode.
In this example, the Anode of the diode
is connected to the Red test clip and the
athode is connected to the Green test
clip, additionally, the Blue test clip is
unconnected. The forward voltage drop
is then displayed, this gives an
indication of the diode technology. In
this example, it is likely that the diode
is a silicon diode. A germanium or
Schottky diode may yield a forward
voltage of about 0.25V. The current at
which the diode was tested is also
displayed.
 Note that the DCA55 will detect only one diode even if two diodes
are connected in series when the third test clip is not connected to the
junction between the diodes. The forward voltage drop displayed
however will be the voltage across the whole series combination.
 The DCA55 will determine that the diode(s) under test is an LED if
the measured forward voltage drop exceeds 1.50V. Please refer to the
section on LED analysis for more information.
D ode or d ode
junct on(s)
RED GREEN BLUE
Anod Cath
Forward voltage
Vf=0.677V
Test current
If=4.300mA

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Diode Networks
The DCA55 will intelligently identify popular types of three
terminal diode networks. For three terminal devices such as
SOT-23 diode networks, the three test clips must all be
connected, any way round. The instrument will identify the type of diode
network and then display information regarding each detected diode in
sequence. The following types of diode networks are automatically recognised
by the DCA55:
Both cathodes connected
together, such as the BAV70
device.
Anodes of each diode are
connected together, the
BAW56W is an example.
Here, each diode is connected
in series. An example is the
BAV99.
Following the component identification,
the details of each diode in the network
will be displayed.
Firstly, the pinout for the diode is
displayed, followed by the electrical
information, forward voltage drop and
the current at which the diode was
tested. The value of the test current
depends on the measured forward
voltage drop of the diode.
Following the display of all the details for the first diode, the details of the
second diode will then be displayed.
Common cathode
d ode network
Common anode
d ode network
Ser es
d ode network
P nout for D1...
RED GREEN BLUE
Cath Anod
Forward voltage
D1 Vf=0.642V

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LEDs
An LED is really just another type of diode, however, the
DCA55 will determine that an LED or LED network has been
detected if the measured forward voltage drop is larger than
1.5V. This also enables the DCA55 to intelligently identify
bicolour LEDs, both two-terminal and three-terminal varieties.
Like the diode analysis, the pinout, the
forward voltage drop and the associated
test current is displayed.
Here, the athode (-ve) LED terminal is
connected to the Green test clip and the
Anode (+ve) LED terminal is connected
to the Blue test clip.
In this example, a simple green LED
yields a forward voltage drop of
1.936V.
The test current is dependant on the
forward voltage drop of the LED, here
the test current is measured as
3.047mA.
 Some blue LEDs (and their cousins, white LEDs) require high
forward voltages and may not be detected by the DCA55.
LED or d ode
junct on(s)
RED GREEN BLUE
Cath Anod
Forward voltage
Vf=1.936V
Test current
If=3.047mA

DCA55 User Guide November 2021 – Rev 14
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icolour LEDs
Bicolour LEDs are automatically identified. If your LED has
3 leads then ensure they are all connected, in any order.
A two terminal bicolour LED consists of two LED chips which
are connected in inverse parallel within the LED body. Three terminal
bicolour LEDs are made with either common anodes or common cathodes.
Here a two terminal LED
has been detected.
This message will be
displayed if the unit has
detected a three terminal
LED.
The details of each LED in the package will then be displayed in a similar way
to the diode networks detailed earlier.
The pinout for the 1
st
LED is displayed.
Remember that this is the pinout for just
one of the two LEDs in the package.
Interestingly, the voltage drop for each
LED (loosely) relates to the different
colours within the bicolour LED. It may
therefore be possible to determine
which lead is connected to each colour
LED within the device. Red LEDs often
have the lowest forward voltage drop,
followed by yellow LEDs, green LEDs
and finally, blue LEDs.
Two term nal
b colour LED
Three term nal
b colour LED
P nout for D1...
RED GREEN BLUE
Anod Cath
Forward voltage
D1 Vf=1.950V
Test current
D1 If=3.033mA