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PRODUCT SHOWCASE Digital multimeter has dual display & bar graph This 3¾ digital autoranging multimeter from Altronics has a wide array of functions which includes capacitance, frequency and hFE measurements. The large liquid crystal display has two 4-digit readouts, an analog bar graph and a large number of annunciators. Among the huge array of multimeters available on the market, the BX-905A stands out as having a very useful range of measurement functions, 16 in total. With most of these functions, special features can be selected such as automatic hold, a relative mode, and a maximum and minimum recording mode with up to 5 memories. Readings are shown on a 14.5mm high 4-digit main display with a smaller 12mm 4-digit display for dual function readings. Both 4-digit displays can indicate up to 3999. The bar graph works in conjunction with the main display and is useful for indicating changes and trends in variable readings. The graph is graduated from 0 to 4 with 32 individual bars. The smaller digital display indicates the range of the bar display: 4, 40, 400 or 1000. The BX-905A multimeter is housed in a tough yellow-orange plastic case measuring 88.5 x 190 x 27.5mm. It weighs about 330g and is supplied with a set of test leads, a 9V battery (installed) and an operating manual. Front panel controls are the rotary function switch which also doubles as an off switch and seven pushbutton switches for special feature selection. There are four input sockets for the multimeter probes; common, the VW and Diode input and the 20A and mA current inputs. An 8-pin circular socket provides for transistor hFE measurements. DC voltage accuracy is claimed as ±0.5% + 1 digit up to 400V and ±0.5% + 2 digits for the 1000V range. The input impedance is 100MW for the 400mV range and 10MW for all other ranges. Maximum input voltage is 1000VDC or 750VAC. AC voltage accuracy is claimed to be within ±0.8% + 3 digits. No frequency response is given in the manual, however we measured the AC response at -3dB down (70.7%) at 5kHz. Low frequency response is limited by the two-second update time of the meter which sets a minimum frequency for a steady reading at around 20Hz. DC current accuracy is ±1.0% + 2 digits for readings up to 2A and ±2% + 20 digits for the 20A range. AC current accuracy is a little higher at ±1.5% + 5 digits up to 2A and ±2.5% + 20 digits for the 20A range. Maximum input voltage for current measurement is 60V DC or 25V AC. The voltage drop across the meter when measuring current (“burden” voltage) is 400mV. Resistance accuracy is ±0.8% + 2 digits for the 400W range and ±0.5% + 2 digits for the 4kW to 4MW ranges. The 20MW range is ±0.8% + 10 digits. Note that the current applied to the resistor under measurement is low enough so that the resultant voltage is below the 0.6V turn on voltage of silicon diodes and transistors. This means that for most measurements you can test resistors while they are still in-circuit. This is quite handy for servicing work. Frequency measurement accuracy is ±0.5% + 1 digit for 10Hz up to 2MHz. The signal must be greater than 1V RMS for frequencies between 10Hz and 100Hz and more than 500mV RMS for frequencies above 100Hz. Capacitance measurement is from 10nF (0.01µF) up to 99.9µF while accuracy is ±3.0% +10 digits. While this is be useful, the lack of ranges from 1pF to 1000pF does make the capacitance function less than ideal. We should note that this criticism applies to most digital multimeters. February 1994  87 Neat 4-channel microphone mixer One big problem with today’s cassette decks is that they usually do not provide facilities for microphones, or if they do, they only cope with a stereo pair. This is where this neat little mixer from Avico Electronics comes into its own. It can be regarded as a four channel stereo mixer or an eight channel mono mixer. It has eight 6.35mm jack sockets for low impedance microphones and two additional jack sockets for the left The diode test function applies a forward DC current of about 1mA to the device under test. The resulting forward drop is displayed on the meter. The test is also suitable for checking transistor junctions and LEDs although the test current is usually insufficient for a LED to produce any significant light output. This function also provides an audible buzzer which can be selected if required. It sounds whenever the resistance is less than about 30W – good for continuity checking on cables and smilar work. The hFE measures transistor DC gain up to 1000. Both NPN and PNP types can be measured in the test socket which caters for transistors with EBC and BCE pin-out configurations. Larger transistors such as those in TOP-3 and T0-3 packages will need to be connected with hookup-wire to the socket. The BX-905A has many LCD an88  Silicon Chip and right stereo outputs. On the front panel there are ten knobs, eight as the individual microphone level controls and two as the master output controls. It is housed in a sturdy steel case with tiny dimensions: 150mm wide, 110mm deep and 55mm high. It is powered by an internal 9V battery or a 9V DC plugpack. Input impedance is 600W and sensitivity is 5mV in for 90mV out. For further information, contact Avico Electronics Pty Ltd, Unit 4/163 Prospect Highway, Seven Hills NSW 2147. Phone (02) 624 7977. nunciators to indicate such selections as the measurement units and the selected mode. When measuring volts, for example, the units displayed are mV or V, with a minus sign indicating negative voltages. An AC annunciator indicates when the AC ranges are selected. If auto-ranging is in effect, AUTO is displayed. You can also select ranges manually with the range switch and then the AUTO annunciator drops out. The MIN/MAX switch enables recording of maximum and minimum values for the function selected. When this feature is selected the MIN MAX annunciator is displayed. To display the minimum value, press the MIN/ MAX switch and for the maximum value press the MIN/MAX switch again. The annunciator indicates whichever reading is displayed. The RELative switch selects difference measurement between the reading displayed the instant the REL switch was pressed and the current input voltage. A small triangle annunciator is displayed in this mode. In auto hold mode, the current reading is frozen on the display. Press the AUTO H switch and the AH annunciator is displayed along with the last reading. The MEMORY switch enables storage of up to five measured values, as indicated by the MEM annunciator. Pressing the RECALL switch brings up the corresponding annunciator and the stored data is displayed. The SHIFT key enables the different features available on a particular function to be displayed. When the ACV function is selected, the shift key selects dB. The display now indicates in dBm where the result is in dB with respect to 1mW into a 600W load. Other shift key functions activate the diode test, hFE and 20A for ACA and DCA measurements. Normally, the smaller digital display shows the selected range of the meter, but when special features are selected the display can show the input value when in the relative and maximum/ minimum modes and the range when in auto hold mode. Meanwhile, the main display shows the relative value, the min, max or the hold value respectively. A special limit feature has also been added to this multimeter. It allows setting of two values, one a high value and one a low value. When the measured value exceeds the high value, the display shows HI. If the value is below the low value the display shows LO and if the value is between the high and low values the display shows PASS. The annunciator shows LIMIT in this mode and the smaller digital display indicates the current reading. The small manual supplied with the BX-905A multimeter provides all the necessary information and detail to allow the owner to become acquainted with the features of this rather complex multimeter. One specification which was not mentioned in the manual is expected battery life. We measured the current drain at 5.5mA which is rather high and this will correspond to about 70 hours of use with a standard zinc-carbon battery. We would strongly suggest the use of an alkaline battery. The meter does have automatic power-down after about 20 minutes of operation. The BX-905A multimeter is priced at $199. An optional holster is available for $15.95 and a carry case for $12.50. These are available from Altronics, 174 Roe Street, Perth WA 6000. Phone (09) 328 2199. Battery eliminator has 850mA output Panasonic’s snap video camera This streamlined battery eliminator is intended for laptop computers, amateur transceivers, car radios and CD players and other appliances which draw higher currents than can be supplied by most plugpacks. It is switchable between 3, 4.5, 6, 7.5, 9 and 12V DC and can deliver up to 850mA. On good feature about the voltage selection is that the slide switch is on the plug side, so it cannot be changed without pulling it output of the socket. This means that there is no chance of the voltage inadvertently being changed while a device is powered up. Another good feature is the red LED which tells you that the unit is powered. The unit has a solid state regulator and overload protection. It comes with four DC plugs, making it compatible with a wide range of DC devices. It is approved to Australian Standard AS-3108. Designated RBE850, the battery eliminator is priced at $54.95 and is distributed by Avico Electronics Pty Ltd, Unit 4/163 Prospect Highway, Seven Hills NSW 2147. Phone (02) 624 7977. A new concept in camcorders, the Panasonic CS1 is designed to run on AA-size alkaline batteries. When the rechargeable batteries run out, the user can attach the alkaline battery case to the camcorder to obtain an extra 60 minutes of video taping. A combination of rechargeable and alkaline batteries can give you up to 135 minutes of recording time and recording with the CS1 is simple. All you need to do is press one button to start and release it to stop recording. The CS1 also features a super wide angle and telephoto lens settings. Wider than on previous models, the 28mm wide angle lens allows you to easily shoot wide scenes, especially indoors, without the need to pan or tilt the camera. For dramatic close-ups, switch to a 3x telephoto lens. The introduction of a self-timer function means the person filming can also be in the picture. When the self-timer is on, the CS1 pauses for 10 seconds and then shoots for 10 seconds. Other features include an LCD screen that shows battery and tape life as well as an auto date recorder, an optical direct finder plus an anti-scratch body. The CS1 uses compact-VHS video tapes, which can be played back and edited by putting them in the supplied cassette adaptor, which fits into a normal VHS VCR. For further information, see your local Panasonic retailer. Entry level programmer DATA I/O have designed and manufactured a programmer for the design engineer or for small volume programming. Capable of programming EPROMSs, (E)EPROMs, PROMs, PALs, FPGAs and MICROs from DIP to PLCC, SOIC, QFP and TSOP packages, it performs Load, Program, Verify, Sumcheck, ID test, Illegal bit test, Blank check, Erase electrically erasable devices, continuity check and PLD testing to 4ns speed. The Menu driven user interface makes it easy to operate from a PC and it has a built in full screen editor for editing EPROM data in Hex and ASCII format. For a complete list of supported devices, please contact Nilsen Instruments, PO Box 30, Concord, NSW 2137. Phone (02) 736 2888. SC February 1994  89