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This is only a preview of the September 2015 issue of Silicon Chip. You can view 44 of the 112 pages in the full issue, including the advertisments. For full access, purchase the issue for $10.00 or subscribe for access to the latest issues. Items relevant to "Senator: 10-Inch Bass Reflex Loudspeakers":
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MARKET CENTRE
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tronixlabs.com - Australia’s best value
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from adafruit, DFRobot, Freetronics,
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sesame<at>sesame.com.au
www.sesame.com.au
LEDs, BRAND NAME and generic
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ledsales.com.au
PCB MANUFACTURE: single to multi
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PCBs & Micros: SILICON CHIP can
supply PCBs and programmed micro-
controllers and other specialist parts for
recent projects and some not so recent
projects: www.siliconchip.com.au or
phone (02) 9939 3295.
MOVING SALE: bargains galore on our
new website. We have to reduce our
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components, mag’s, books, etc.
www.questronix.com.au
KIT ASSEMBLY & REPAIR
VINTAGE RADIO REPAIRS: electrical mechanical fitter with 36 years ex
perience and extensive knowledge of
valve and transistor radios. Professional
and reliable repairs. All workmanship
guaranteed. $10 inspection fee plus
charges for parts and labour as required.
Labour fees $35 p/h. Pensioner discounts available on application. Contact
Alan on 0425 122 415 or email bigal
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DAVE THOMPSON (the Serviceman
from SILICON CHIP) is available to help
you with kit assembly, project troubleshooting, general electronics and
MaxiMite . . .
miniMaximite
or MicroMite
The versatile Australian Computer!
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Read the articles – and you’ll be convinced . . .
You’ll find all details at:
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PCBs & Micros available from PartShop
custom design work. No job too small.
Based in Christchurch, NZ but service
available Australia/NZ wide. Phone
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davethompson.co.nz
KEITH RIPPON KIT ASSEMBLY &
REPAIR:
* Australia & New Zealand;
* Small production runs.
Phone Keith 0409 662 794.
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. . . continued from page 109
rent to suit smaller batteries?
I have noticed that there are a few
battery checkers for sale at the moment. One that crops up a bit in an
internet search uses the method below. It is around $70 on eBay. They
are typically described as: “This Battery Analyzer is designed to test the
condition of the automotive battery
using conductance method. Unlike the
conventional method of draining the
battery by applying resistance load to
siliconchip.com.au
it and obtain the result from the meter
gauge; this analyzer utilizes a series of
pulsed voltage across the battery cells
and observes the AC current that flows
in response to it”.
I cannot bring myself to buy it as
I cannot convince myself that it will
work. I am thinking that as your design is now over six years old, it may
be worthwhile designing a updated
model? (R. M., via email).
• You may be right in wondering if a
test pulse current of 12A may be too
great for small SLA batteries, at least
for those rated at 4.4Ah and below.
Lifting the earthy end of say two of
the 0.22Ω 5W resistors via an added
switch would certainly drop the pulse
current for the three range settings of
switch S2 to 8.2A, 13.6A and 19.1A .
The 8.2A figure would probably
be OK, even for a 4.4Ah SLA battery.
However, this would also mean that
only two of the switching Mosfets
would have to share the load.
A better way might be to lift the
earthy ends of all four 5W resistors
and run them to earth via an added
switch. Then, in addition, connect two
0.1Ω 5W resistors in parallel across the
switch, so that when it’s in the open
. . . continued on page 112
September 2015 111
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