This is only a preview of the September 1995 issue of Silicon Chip. You can view 34 of the 104 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. Articles in this series:
Articles in this series:
Articles in this series:
Items relevant to "Notes On The Train Detector For Model Railways":
Items relevant to "Build A Jacob's Ladder Display":
Articles in this series:
|
PRODUCT SHOWCASE
Protek 505 digital multimeter
has dual display
This Protek 505 digital multimeter has a
large dual digital display plus bar graph, true
RMS readings, memory storage and 4000
count resolution. As well, it will measure
temperature, frequency, capacitance and
inductance.
While all multimeters will perform
voltage, current, resistance and diode
tests, there are not many which can
also measure temperature, frequency,
capacitance, inductance, logic levels
and dBm values. You can also measure
time period for stop watch or alarm
functions and store measured values
in up to nine memory locations. The
Protek 505 also includes a signal generator with three output frequencies
(2048, 4096 and 8192Hz square wave).
Naturally it is autoranging and this can
be overridden if required.
The Liquid Crystal Display (LCD)
has a dual digital readout and bar
graph plus numerous annunciators.
This dual readout allows two measurements to be displayed and measured
at once. For example, when measuring
AUDIO
TRANSFORMERS
Manufactured in Australia
Comprehensive data available
Harbuch Electronics Pty Ltd
9/40 Leighton Pl. HORNSBY 2077
Ph (02) 476-5854 Fx (02) 476-3231
92 Silicon Chip
frequency, the display will show the
reading in Hz on the main display and
the value of AC volts on the secondary
scale. When the time display is selected, this is shown on the secondary
scale with the measured value of volts,
current, temperature or resistance on
the main digits.
There is no skimping on the size
of the display either. The main and
secondary display digits are 19mm
and 9mm high respectively while the
bar graph displays from 0 to 40 with
21 active segments.
The word "active" is used because
the display appears to have 37 segments, however, 16 of these are doubled up so that they are "lit" together.
Knowing this is important for attempting to read the bargraph value. The
bargraph is useful for seeing the trend
of value changes which can be too fast
for the digital display to update. The
display can be backlit for use in dark
locations.
Most of the functions available can
be manipulated to provide maximum,
minimum, average and relative readings. These are accessed using the
menu key. Once this key has been
pressed though, there is no way out;
you are stuck with selecting either
Max, Min, Avg, Rel or Keep On unless power is switched off. We would
prefer to have an Out selection which
restores the meter to provide normal
readings.
The relative (Rel) display is useful
when there is a fixed offset in the
measurement. This can be subtracted
so that only the change is displayed.
Relative readings can also be displayed
as a percentage change from the reference value.
A hold feature freezes the display
at any time so that no further changes
in the reading take place. Readings
can also be placed in memory for a
more permanent storage. There are 9
memories available, labelled 1-9. The
"0" memory location is innactive and
cannot be used for storage. It can be
recalled but it only shows 0000. The
handbook indicates that this memory
location is not useable, however, they
also claim that there are 10 memory
locations! The memory locations are
not erased when the meter turns off in
the auto power off mode.
To prevent the meter from switching
off after 30 minutes of inactivity, a
"keep on " facility is available which
disables the automatic power off.
Naturally, the meter can be turned on
and off at will using a separate push
button switch. The handbook recommends switching off manually rather
than waiting for the automatic power
Optical light sources
& power meter
Tektronix has introduced a
new line of handheld optical test
products that include the TOP130,
TOP140 and TOP150 optical light
sources, the TOP200 power meter
and the TOP300 visual fault finder.
The TOP130 emits at 850/1300nm
and is suitable for testing multimode cable used in LANs and
WANs; the TOP140 laser source
emits at 1310nm and the TOP150 laser source emits at 1550nm. Models
TOP140 and TOP150 are used for
testing single mode cables in Telco
and CATV networks.
All the light sources feature a
off feature. This would be a good idea
since battery life is only about 60 hours
with a carbon zinc battery. Fortunately, a low battery warning indicator is
included so that you will know when
to replace it and a separate battery
compartment is provided allowing
easy access.
Diode readings display the foreward
voltage measured between anode and
cathode on the secondary display.
The main display shows either SHrt
(short), OPEn or Good. These are supposed to tell you whether the diode
is operating correctly. We found that
good Schottky and high speed diodes
universal connector interface for easy
upgrade and cleaning. Battery life is
claimed to be over 100 hours with
standard alkaline batteries.
A companion product to Tektronix
optical light sources is the TOP200
optical power meter. It is a lowcost, palm-size unit that makes the
basic optical power measurements
in either dB or dBm, calibrated at
850nm, 1300nm and 1550nm. This
power meter provides 0.01dB resolution and allows the user to store
reference values for each wavelength
independently.
For further information, contact
Tektronix Australia Pty Ltd, 80 Waterloo Road, North Ryde, NSW 2113.
Phone (02) 887 7066.
gave a "short" indication because their
forward voltage was below 0.5V. The
diode test provides up to 4V and so
LEDs can be tested. The LED will
light up and an open indication will
be given because the forward voltage
of the LED is greater than 1V. Some
discretion must therefore be used
when interpreting the short and open
indications.
Temperature sensing must be done
using a "K" type thermocouple, which
is available as an accessory. The probe
can measure temperature from -20 to
1200 degrees C which is then shown
on the main display. The secondary
September 1995 93
Video magnifier uses
CCD camera
This 1/2" colour CCD high resolution video camera/microscope
provides 10x, 20x and 40x magnification with greater than 450 lines
horizontal resolution.
The SVC-228 offers advantages
over magnifying glasses and other
optical inspection devices. Several
or groups of people can simultaneously observe the image for
discussion; images may be recorded
on a VCR or by using an interface
card stored, in a personal computer
for documentation, manipulation,
measurement or printout.
The SVC-228 comprises a main
unit which houses the power
supply and interface circuitry and
connects via a 2 metre cable to the
camera head.
Optional lenses provide a choice
of magnification. Also available
is an adjustable stand with lamps
display shows the Fahrenheit value.
With no probe connected, the readout will show ambient temperature
and is useful for finding out why you
feel cold (we reviewed this meter in
winter!).
While the meter can read inductance it is restricted values above 10mH
which is a relatively large value in
practice. Most inductances used in RF
and switchmode supplies are much
smaller than this. Note also that if the
Q is less than 10 or the coil resistance
is greater than 100W, then inaccuracies
will result.
Capacitance measurement range is
better, at up to 100µF with a 0.01µF
resolution. This means that you can
measure 10nF and larger up to 99µF.
Audio Lab
for illumination. Applications
include assembly and inspection
of mechanical parts, components,
surface mount devices, printed circuit boards, contacts, connectors,
measurement, quality control and
verification.
For further information contact
Allthings Sales & Services, PO Box
25, Northlands, WA 6021. Phone (09)
349 9413 or fax (09) 344 5905.
We would have preferred to be able
to measure much smaller values than
10nF (.01µF).
The frequency meter mode can be
used for measurement from 1Hz up to
9999MHz with 4 digit resolution. The
input signal for the frequency mode is
a minimum of 1.5V RMS (4.24V p-p).
This is find for CMOS and TTL circuits
but most analog and RF circuits will
need a preamp/buffer for meaningful
measurements.
Incidentally, the meter incorporates
a logic level range which indicates
a logic Hi and logic Lo on the main
display. The in-between voltage where
the logic is indeterminate is indicated
by a "....". Logic voltage is set for TTL
levels and so it is suitable for High
R.S.K. Electronics Pty. Ltd.
Complete Audio Lab kit with PCBs, 1% resistors, PTH screened PCBs, IC sockets,
boot Eprom, screen printed case, 8K RAM, 8031 processor and all ICs.
Includes calibration and Audio Lab V5.1 software
10 VAC 1A plugpack plus socket $18.
2-Metre serial cable $9.
$330 inc. tax.
Processor test kit $15.
Freight $9.
Fully assembled & calibrated complete with plugpack (1-year warranty) $450
5 Ludwig Place, Duncraig, Perth WA 6023
94 Silicon Chip
Phone (09) 448 3787
Speed CMOS as well.
Three output frequencies are
available from the meter. These are
at 8192, 4096 and 2048Hz with a 4V
p-p minimum output. The source impedance is 1.5kW so that it can drive
logic circuitry. Interestingly enough,
the signal swings between -0.7V and
+3.3V. The is indicates that the internal
signal generator must be AC coupled
with a diode clamp to prevent the
negative excursion going beyond one
diode drop.
Timer counting is available for up
to 10 hours with a count rate of one
second. You can count up from zero
to 9Hr 59min 59sec and the alarm will
sound one second after this maximum
count has been reached. The counter
is presettable to any time within this
range. Counting down is also possible. In this case, however, the alarm
sounds one second after 0.00.00 has
been reached.
AC voltage measurement is true
RMS. This means that the correct reading is obtained for waveforms other
than pure sine waves. On a normal
meter without true RMS readings, the
display is calibrated to give a correct
RMS reading only for sine waves.
With true RMS, the reading is essentially correct for other types of waves.
For example, the additional error in
reading compared to the sine wave for
square and triangle waves is 0.2% and
0.3% respectively. For crest factors up
to 2, the additional error is 0.5%. For
accuracy details see the latter part of
this review.
Also on the AC voltage range is
displayed a dBm reading on the secondary display. A reading of 0dBm
means that the voltage is 0.7746V.
This corresponds to 1mW into a 600W
load and all dBm values displayed are
referenced to this level.
Continuity measurements are available with or without a tone. With tone
selected the meter will register an
OPEn condition above 100W and will
show a short otherwise. Without the
tone selected, the meter only shows
the value in ohms.
Accuracy
The Protek 505 has ±0.3% +2 digits
accuracy for the 400mV DC range. For
the 4V to 1000V ranges, the accuracy is
±0.5% +2 digits. AC voltage accuracy
is ±1% +3 digits for the 400mVAC
range from 50Hz to 1kHz. The 4VAC
to 750VAC ranges are ±1.5% +5 digits
accuracy from 50Hz to 100Hz for the 4VAC range and up to
500Hz for the remaining ranges.
Resistance accuracy is ±0.5% +2 digits up to 400kW and
1% +2 digits for ranges above this. DC current accuracy
is ±1% +2 digits and AC current is ±1.5% +3 digits from
50Hz to 100Hz. This rises to ±3% +5 digits from 100Hz
to 1kHz.
Frequency accuracy is ±0.01% ±2 digits. Temperature
accuracy is ±3% +5 digits from -20 to 10 degrees C. It is ±3%
+3 digits from 10 to 350 degrees C. Capacitance accuracy
is ±3% +5 digits and inductance accuracy is the same for
values up to 20H.
The meter is fully protected from over voltage and over
current using fuses and a PTC thermistor. A spare 0.5A fuse
is included inside the case, however, there is no spare 20A
fast blow type included.
The meter is supplied in a vinyl case which also holds
the probe leads and handbook. The probes have two screwon aligator clips for the probe tips which are a worthwhile
inclusion.
In short, the Protek 505 is a lot of meter for the money.
With true RMS measurement, dual display, bar graph and
a host of measurement functions, it will be a popular unit.
It is priced at $229 including tax and is available from Altronics in Perth or from their dealers Australia wide. Phone
1 800 999 007.
Fast response
oxygen probe
Novatech Controls have
developed a fast responding
oxygen sensing probe for flue
gas, furnace and kiln applications. The development
program was in response to
market demands from within
Australia and overseas.
The zirconia sensor has a
response time in the millisecond region but is extended by the time taken to introduce the gas sample from the
process to the sensor. This
total speed of response time can be critical, particularly in
automatic combustion trim systems.
The Novatech development, which was the result of
extensive wind tunnel testing, provides users with a probe
which will respond to changes in the oxygen level of the
sample within four seconds. It has an optional 10 micron
particulate filter for flues with fly ash or other material which
can block up sensing ports.
The benefit to users of fast responding flue gas oxygen
sensing probes is improved trim control of combustion
air/fuel ratio. This means savings in fuel. In some critical
cases where process measurement lag cannot be tolerated,
automatic control may be implemented where it was not
previously possible.
Novatech oxygen probes use advanced zirconia cell technology developed by the CSIRO Division of Materials Science
and Technology. For further information, contact Novatech
Controls (Aust) Pty Ltd, 429 Graham St, Port Melbourne, Vic
3207. Phone (03) 9645 2377 or fax (03) 9646 3027.
KITS-R-US
PO Box 314 Blackwood SA 5051 Ph 018 806794
TRANSMITTER KITS
$49: a simple to build 2.5 watt free running CD level input, FM band runs from 12-24VDC.
•• FMTX1
FMTX2B $49: the best transmitter on the market, FM-Band XTAL locked on 100MHz. CD level input 3
stage design, very stable up to 30mW RF output.
$49: a universal digital stereo encoder for use on either of our transmitters. XTAL locked.
•• FMTX2A
FMTX5 $99: both FMTX2A & FMTX2B on one PCB.
FMTX10
$599:
FMTX5 built and tested, enclosed in a quality case with plugpack, DIN input
•connector for audioa complete
and a 1/2mtr internal antenna, also available in 1U rack mount with balanced cannon
input sockets, dual VU meter and BNC RF $1299. Ideal for cable FM or broadcast transmission over
distances of up to 300 mtrs, i.e. drive-in theatres, sports arenas, football grounds up to 50mW RF out.
FMTX10B $2599: same as rack mount version but also includes dual SCA coder with 67 & 92KHz
subcarriers.
•
AUDIO
Audio Power Amp: this has been the most popular kit of all time with some 24,000 PCBs being
•soldDIGI-125
since 1987. Easy to build, small in size, high power, clever design, uses KISS principle. Manufacturing
rights available with full technical support and PCB CAD artwork available to companies for a small royalty.
200 Watt Kit $29, PCB only $4.95.
AEM 35 Watt Single Chip Audio Power Amp $19.95: this is an ideal amp for the beginner to construct;
uses an LM1875 chip and a few parts on a 1 inch square PCB.
Low Distortion Balanced Line Audio Oscillator Kit $69: designed to pump out line up tone around studio
complexes at 400Hz or any other audio frequency you wish to us. Maximum output +21dBm.
MONO Audio DA Amp Kit, 15 splits: $69.
Universal BALUN Balanced Line Converter Kit $69: converts what you have to what you want, unbalanced
to balanced or vice versa. Adjustable gain. Stereo.
•
•
••
COMPUTERS
I/O Card for PCs Kit $169: originally published in Silicon Chip, this is a real low cost way to interface
•to Max
the outside world from your PC, 7 relays, 8 TTL inputs, ADC & DAC, stepper motor drive/open collector
1 amp outputs. Sample software in basic supplied on disk.
PC 8255 24 Line I/O Card Kit $69, PCB $39: described in ETI, this board is easy to construct with
•onlyIBM3 chips
and a double sided plated through hole PCB. Any of the 24 lines can be used as an input or
output. Good value.
Professional
19" Rack Mount PC Case: $999.
•• All-In-One 486SLC-33
CPU Board $799: includes dual serial, games, printer floppy & IDE hard disk drive
interface, up to 4mb RAM 1/2 size card.
PC104 486SLC CPU Board with 2Mb RAM included: 2 serial, printer, floppy & IDE hard disk $999; VGA
•PC104
card $399.
KIT WARRANTY – CHECK THIS OUT!!!
If your kit does not work, provided good workmanship has been applied in assembly and all original parts
have been correctly assembled, we will repair your kit FREE if returned within 14 days of purchase. Your
only cost is postage both ways. Now, that’s a WARRANTY!
KITS-R-US sell the entire range of designs by Graham Dicker. The designer has not extended his agreement
with the previous distributor, PC Computers, in Adelaide. All products can be purchased with Visa/Bankcard
by phone and shipped overnight via Australia EXPRESS POST for $6.80 per order. You can speak to the
designer Mon-Fri direct from 6-7pm or place orders 24 hours a day on: PH 018 80 6794; FAX 08 270 3175.
Pattern generator for
TV & computer monitors
Obiat Pty Ltd has introduced the Black Star 1410 video
monitor tester, a microprocessor controlled instrument
for aligning and testing computer and TV monitors and
video projectors.
The comprehensive range of line and frame frequencies, together with the variety of rear panel outputs,
ensure compatibility with the majority of computer
monitors.
The Black Star 1410 produces a wide range of test
patterns which includes a testcard, raster, vertical and
horizontal lines, colour bars, checkerboard, dots and a focus function. The selected pattern, system, sync. polarity
and line/frame frequencies are shown on the unit's liquid crystal display. It is suitable for CGA,
MDA, PGA,
VGA, SVGA
and 8514A/
XGA computer displays in
addition to TV
monitors. Factory-programmed versions of the 1410 are
also available.
For more information, contact Obiat Pty Ltd, 129 Queen
Street, Beaconsfield, NSW 2014. Phone (02) 698 4111 or
fax (02) 699 9170.
September 1995 95
|