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PRODUCT SHOWCASE Tektronix P5200 high-voltage differential probe The measurement of high voltage or AC mains voltage signals presents problems that are not easily overcome with standard dual channel oscilloscopes. One solution is to use a Tektronix P5200 high voltage differential probe. The attenuators of most general purpose oscilloscopes pro­ v ide a maximum input sensitivity of 5V/ division. With the screen displaying eight vertical divisions this means that the maximum input signal can only be 40V peak-to-peak with a direct probe or 400V peak-to-peak using a 10:1 divider probe. Larger signals can be displayed using the variable input control but then the ampli­tude measurement facility is lost. If the signal to be measured is a mains AC wave­form or other higher voltage which is not ground referenced then it can be displayed using a dual trace oscilloscope in the Add mode. Once again the maximum calibrated display voltage will be 400V peak to peak. As an alternative, some organisations adopt the practice of using an oscilloscope with its mains earth dis­connected to display floating and mains voltages. This is a highly dangerous procedure with nothing to recommend it. Displaying the mains voltage waveform using a regular probe with the tip connected to the active lead and the earth clip connected to the neutral is also a dangerous procedure. Trans­po­sition of the live and neutral connections to the probe is always a possibility and if this mistake is made then the best that can happen is a blown fuse and the worst is electrocution. What is really required is an instrument with a differen­tial input, some level of signal attenuation and a single ended output signal to apply to the following measuring equipment. To cater for signals with fast rising wave fronts – eg; SCR circuits, switchmode supplies, etc – it should also have a wide bandwidth and fast rise time. The Tektronix P5200 high voltage differential probe meets all these requirements and allows the aforementioned measurements to be made easily and safely. It is supplied with two sets of connectors and a 9VDC 1A plugpack power supply. One Table 1: Specifications Maximum applied voltage between either input and ground............ 1kV (DC + peak AC) Maximum applied voltage between inputs.................................... 1.3kV (DC + peak AC) Rise time .........................................................................................<14ns in 1/50 range DC CMRR .........................................................................................>5000:1 at 500VDC AC CMRR................................................ 60Hz >10000:1; 100kHz >300:1; 1MHz >300:1 Bandwidth ..................................................................DC to 25MHz (-3dB) in 1/50 range Maximum operating input voltage.................... 1/500 differential 1.3kV (DC + AC peak); 1/500 common mode, 1kV (DC + AC peak); 1/50 differen­tial, 130V (DC + AC peak); 1/50 common mode, 1kV (DC + AC peak) Range accuracy................................... ±3% between 20-30°C after 20 minute warmup. Input impedance........... 8MΩ + 3.5pF between inputs; 4MΩ +7pF each input to ground DC output drift............................................................................................... ±0.5mV/°C Propagation delay.................................................................................................... 20ns Operating temperature range ............................................................................... 0-40°C January 1996  63 pair of connectors are long reach plunger probes and the other pair are heavy duty, double insulated crocodile clips. Its dimensions are 185mm (L) x 66mm (W) x 32mm (H). Two 500mm long input connectors are at one end of the case and these are terminated with shrouded plugs to fit the probe connectors. At the other end of the case is a 1500mm long output lead termi­ n ated with a moulded plug that carries an input socket for the plugpack and a 300mm long coaxial lead terminated with a BNC male plug to supply output to the measuring instrument which will usually be an oscilloscope. The face of the probe case features a pushbutton switch which provides 1/500 or 1/50 attenuation to the input signal. There are also LEDs for Power and Over Range and a table showing the effective volts/division of the combined probe plus oscillo­scope for different settings of the oscilloscope’s input attenua­tor. Output level from the probe is a maximum of 2.6V. The specifications for the P5200 are shown in Table 1. We used a sample P5200 in our laboratory and found that it does all that is claimed for it. It enables safe and accurate measurements when the source is not referenced to ground, par­ t icularly where mains voltage signals are concerned. In addition, it offers a much higher common mode rejection ratio than any typical dual channel oscilloscope when used in the “Add” mode – an important advantage. The Tektronix P5200 is priced at $658 plus sales tax where applicable. For further information, contact Tek­ tron­ix Australia Pty Ltd, 80 Waterloo Rd, North Ryde, NSW 2113. Phone (02) 888 7066 or fax (02) 888 0125. Fast-charger IC for lead-acid batteries Reptechnic has introduced the Benchmarq bq2031 lead acid fast charge IC. This incorporates current and voltage regulation with fast charge control to produce a highly cost effective fast charge system. Available in a 16-pin narrow DIP or SOIC package, the bq2031 is designed for controlling constant voltage and constant current charging of lead acid batteries in emergency lighting, backup power, industrial equipment and consumer elec­tronics applications. It can be configured for linear or gated current regulation applications. The bq2031 meets the battery manufacturers’ charge recom­mendations for both cyclic and float/maintenance charge. It includes a flexible pulse width modulation regulator which is suitable for high efficiency switch­ mode designs. Direct LED control outputs are featured for displaying charge status and fault conditions. Pre-charge qualification tests have been per­ formed on the device for shorted, open or damaged cells, allow­ ing it to condition the battery for fast charge. Charging is also qualified by selectable temperature and voltage 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: a complete FMTX5 built and tested, enclosed in a quality case with plugpack, DIN input •connector for audio 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. 19" Rack Mount PC Case: $999. •• Professional 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. 64  Silicon Chip AV-COMM PTY LTD www.avcomm.com.au PCB POWER TRANSFORMERS 1VA to 25VA allow designers to experiment with the bq2031. For further information, contact Reptechnic, 3/36 Bydown St, Neutral Bay, NSW 2089. Phone (02) 9953 9844. Jaycar kits now made under AS9002 Manufactured in Australia Harbuch Electronics Pty Ltd 9/40 Leighton Pl. HORNSBY 2077 Ph (02) 476-5854 Fx (02) 476-3231 limits. Key specifications include temperature, float voltage reference, pin select­able charge and maintenance modes, and pin selectable charge termination by maximum threshold voltage, minimum current and maximum time. A switchmode development system, the DV2031S1, is available to Pocket-sized fax machine & organiser Now available at Dick Smith Electronics, the Handifax 1000 is a 256K electronic personal organiser and fax machine in one. In a lightweight, compact 72 x 198mm unit, Handifax 1000 gives you the capability of faxing your colleagues and clients any­where, any time, by simply using it in conjunction with a stan­dard touch tone tele­phone or analog mobile phone. Simply type the message you want to fax, place the handset of the tele­ phone or mobile phone on the acoustic The head office, warehouse and kit department of Jaycar Electronics has successfully passed all requirements and has been accredited to AS/NZ ISO 9002:1994. “We realised that sooner or later we would have to seek this level of quality of management, documentation and quality control,” commented Managing Director, Gary Johnston. “As it turned out, our existing organisation was close to the high standards required anyway, so achieving the AS9002 level of quality was not particularly difficult. Our kits have always been very high quality. Now we have independent proof that they are.” According to Mr Johnston, the quality accreditation is part of an ongoing commitment by Jaycar to provide a high standard of service in the indus­try. YOU CAN AFFORD AN INTERNATIONAL SATELLITE TV SYSTEM SATELLITE ENTHUSIASTS STARTER KIT YOUR OWN INTERNATIONAL SYSTEM FROM ONLY: FREE RECEPTION FROM Asiasat II, Gorizont, Palapa, Panamsat, Intelsat coupler speaker and microphone, dial the fax machine you are calling and press SEND. Handifax 1000 can communicate with any standard fax machine at speeds of up to 9600 bps. Quick and simple to use, it will hold up to 120 faxable pages and its auto dialling facility ensures that there is no need to manually dial numbers or access codes. The unit has built-in fax cover pages and the ability to customise fax headers, standard orders, invoices, etc. With a 256K memory, Handifax 1000 also doubles as a person­al organiser, capable of storing more than 3500 entries. A 7-digit password can be used to protect all data. An optional PC interface allows users to back up and store information on any standard IBM compatible PC. The Handifax comes complete with an operation manual, an instruction video and is available at all Dick Smith Electronics stores for just SC $699. HERE'S WHAT YOU GET: ● ● ● ● ● ● 400 channel dual input receiver preprogrammed for all viewable satellites 1.8m solid ground mount dish 20°K LNBF 25m coaxial cable easy set up instructions regular customer newsletters BEWARE OF IMITATORS Direct Importer: AV-COMM PTY. LTD. PO BOX 225, Balgowlah NSW 2093 Tel: (02) 9949 7417 / 9948 2667 Fax: (02) 9949 7095 VISIT OUR INTERNET SITE http://www.avcomm.com.au YES GARRY, please send me more information on international band satellite systems. Name: __________________________________ Address: ________________________________ ____________________P'code: __________ Phone: (_______) ________________________ ACN 002 174 478 January 1996  65