Peak Atlas SCR100 User manual

Atlas SCR100
Triac and Thyristor Analyser
Model SCR100 (Firmware: 4.0)
Desi ned and manufactured with pride in the UK
User Guide
© Peak Electronic Desi n Limited 2004/2021
In the interests of development, information in this uide is subject to chan e without notice.
E&OE
EN100-9

Atlas SCR100 User Guide November 2021 – Rev 9
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Want to use it now?
We understand that you want to use your SCR100 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
afety Considerations .......................................................... 4
Analysing components ........................................................ 5
CRs .............................................................................. 6
Triacs ............................................................................. 7
Notes on CRs (Thyristors) and Triacs ............................... 8
Gate ensitivity ................................................................. 10
Gate Voltage ..................................................................... 11
Care of your SCR100 ........................................................ 12
Battery Replacement.................................................... 12
elf Tests ..................................................................... 13
Appendix A – Accessories ................................................ 14
Appendix B – Technical pecifications ............................ 15
Appendix C – tatutory Information ................................. 16
This user guide has been written to accompany the SCR100 with revision 4.0
firmware. Other revisions of firmware may differ in operation, features and
specifications. The firmware version is displayed briefly upon power-up.

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Introduction
The Peak Atlas SCR100 is an advanced instrument designed
specifically for the analysis of CR (Thyristor) and Triac
devices.
Summary Features:
• Automatic component identification (Thyristor or Triac).
• Automatic pinout identification.
• Displays actual trigger (gate) current classification.
• Measures gate voltage during trigger.
• Fixed load current of 100mA.
• Unique automatic boost function ensures a device test
voltage of 12V regardless of battery condition.
• uitable for devices requiring gate currents up to 90mA.
• Automatic and manual power-off.

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Safety Considerations
WARNING:
T is instrument must NEVER be connected to powered
equipment/components or equipment/components wit
any stored energy (e.g. c arged capacitors).
Failure to comply wit t is warning may result in
personal injury, damage to t e equipment under test,
damage to t e SCR100 and invalidation of t e
manufacturer's warranty.
“Analysis of discrete, unconnected components is
recommended.”


 The SCR100 is designed to provide accurate and
reliable information for the majority of supported
component types ( CRs and Triacs) as described in this
user guide. Testing of other component types or
component networks may give erroneous results and may
also cause damage. It is important that you familiarise
yourself with the test conditions presented by this
instrument as shown in the technical specifications.

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Analysing Components
The SCR100 is designed to analyse discrete, unconnected, unpowered Triacs
and Thyristors. This ensures that external connections don’t influence the
measured parameters. The three test probes can be connected to the
component any way round.
The SCR100 will start component
analysis when the on-test button is
pressed.
The analysis typically takes less than a second 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.
If the SCR100 cannot recognise the component connected to the test probes,
or the component under test is outside the specifications covered by this
instrument, the following message will be displayed:
Note:
An arrow symbol on the display indicates that more pages are
available to be viewed.
The unit will switch off automatically after a period of inactivity, however the
unit can be switched off manually by pressing and holding the scroll-off
button for around 1 second.
Analysing...
No SCR or Triac
detected.

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Silicon Controlled rectifiers
(Thyristors
The SCR100 will analyse almost any CR provided that a gate
trigger current of no more than 90mA is required.
The three test clips can be connected to
the device under test any way round. If
the SCR100 detects an CR, the
following message will be displayed:
Pressing the scroll-off button will
then display the pinout details for the
device.
In this example, the Anode of the CR is connected to the Red test clip, the
Cathode is connected to the Green test clip, and the Gate terminal is connected
to the Blue test clip. The gate trigger current is displayed on the next screen.
Note that CRs are often only specified
to have a certain maximum trigger
current – the actual (tested) trigger
current may be well below that value.
SCR detected
Press scroll...
RED GREEN BLUE
Anod Cath Gate
Trigger current
I G 50mA to 60mA

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Triacs
The SCR100 will analyse almost any Triac, provided that it
requires a gate trigger current of no more than 90mA. The
three test clips can be connected to the device under test any
way round. If the SCR100 detects a
Triac, the following message will be
displayed:
Note: The device under test will be analysed in quadrants 1 and 3. The
definition of these quadrants is given later in this guide.
Pressing the scroll-off button will
then display the pinout details for the
device.
In this example, the MT1 terminal of the Triac is connected to the Red test
clip, the MT2 terminal is connected to the Green test clip, and the Gate
terminal is connected to the Blue test clip. The gate trigger current is
displayed on the next screen. Note that Triacs are often only specified to have
a certain maximum trigger current – the actual (measured) trigger current may
be well below that value.
The gate trigger current
1
displayed is
that for quadrant 3. (Quadrant 1 will
usually be very similar).
The load current at which the Triac was tested is also displayed. This value is
fixed for all devices, and simply serves as a reminder. The symbol indicates
that this is the final page of information. Pressing the scroll-off button again
will return the display to the first page of information.
Note 1. ee the “Gate ensitivity” section later in this guide.
Triac detected
Press scroll...
RED GREEN BLUE
MT1 MT2 Gate
Trigger current
I G 10mA to 25mA

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Notes on SCRs and Triacs
Silicon Controlled Rectifiers (T yristors)
SCR Turn-On
CRs (Thyristors) act as a controlled diode. They
block reverse current between the cathode (K) and
the anode (A) at all times, and they conduct in the
forward direction only when triggered by a pulse of
current to the control (gate) terminal. Once
triggered, the CR will continue to conduct current
in the forward direction between the anode and the
cathode until the device is turned off.
SCR Turn-Off
In order to turn off a triggered CR, it is necessary to reduce the anode-
cathode load current below the holding current for typically 5-200s. horter
periods may leave insufficient time for free charge carriers to recombine, and
thus when load current is reapplied, the device may remain triggered.

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Notes on SCRs and Triacs
Triacs
Triacs are a well established technology, designed
specifically for the solid-state control of AC loads. They
offer bi-directional load current switching (for both half
cycles of the mains supply) and also bi-directional gate
current capability to trigger the device. The combinations of
the load currents and gate control currents are referred to as
“quadrants”. These quadrants are shown below:
The main load current is handled by
the connections MT1 and MT2. The
device is switched to the on state by
a current into (or out of) the gate
terminal with respect to the MT1
terminal.
Once triggered, main load current
will continue to flow until a zero-
cross in the mains cycle is
encountered, at this point the device
switches off. Therefore, if the
device is to be kept on, a
continuous gate current must be
provided or at least a gate current
pulse that occurs immediately after each mains zero-cross.
Many triacs however are only capable of operating reliably in 3 of the 4
quadrants. (In particular, Q1, Q2 and Q3). Quadrant 4 (negative gate current
and negative load current) can be troublesome with some triacs, suffering
from poor gate sensitivity and slow response.

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Gate Sensitivity
The SCR100 attempts to trigger the device under test at nine discrete gate
currents, in ascending order.
Trigger level 1 100

A
Trigger level 2 1mA
Trigger level 3 10mA
Trigger level 4 25mA
Trigger level 5 35mA
Trigger level 6 50mA
Trigger level 7 60mA
Trigger
level 8
75mA
Trigger
level
9
90mA
As an example, a reported trigger current of 10-25mA means that device
triggering occurred at a gate current of 25mA, but not at 10mA. Therefore the
trigger current for the device under test is between 10mA and 25mA.
Although Triacs are tested in both quadrants 1 and 3, the reported gate trigger
current is that which applies to quadrant 3.
First test
Last test