This very simple toy uses a magnetic chain reaction to launch a steel marble at a target at high speed. The toy is very simple to build, going together in minutes, and is very simple to understand and explain, and yet fascinating to watch and to use.
The photo above shows six frames of video showing the gauss rifle in action. Each frame shows 1/30th of a second. In the first frame, a steel ball starts rolling towards a magnet taped to a wooden ruler. In the second frame, a second ball can be seen speeding between the rightmost two magnets. By the third frame, the accelerator has sped up so much that the ball that is seen leaving the left side of the device is just a blur as it smashes into the target. One ball, starting at rest, has caused another ball to leave the device at a very high speed.
S:sci-toys.com
The candle flame will heat up the magnetic material until it loses its ability to be magnetized. Gravity will then pull it away from the magnet (and thus away from the flame). The magnetic material will cool down a little bit once it is away from the flame, and regain its ability to stick to the magnet. The magnet will then pull it up into the flame, and the whole process repeats.
All the parts can be found at Radio Shack, but if you want to build the engine using a Canadian nickel, any hardware store will have the other parts you need.
You will need some copper or brass wire, a large ceramic magnet (the cheap kind that Radio Shack sells for about a dollar), and a candle.
We want the pendulum to swing back and forth only, so we use two wires to hold it up. Cut about a foot of wire and wrap the center of the wire around the large magnet. Then form the two ends into small loops and bend them up to form the support for the pendulum.
If you are using the rare-earth magnet for the pendulum's weight, it helps at this point to demagnetize it by holding it in a candle flame. You can stick it onto a coat hanger and hold the magnet in the flame until it falls off. This will prevent the magnet from jumping onto the large ceramic magnet while we adjust the pendulum.
Wrap another foot of wire around the nickel or the rare-earth magnet that will form the weight for the pendulum. Form the two ends of the wire into loops that slip into the loops of the pendulum support. Make sure that the pendulum weight is just close enough to the magnet that it rises to it when the pendulum is vertical. The wires of the pendulum and its support should be long enough that the weight can fall away from the flame and hang vertically when it is demagnetized.
With the pendulum stuck to the large magnet, position a short (lighted) candle so that the flame just touches the weight. You may need to shield the flame from drafts so it remains steady. The flame will heat the rare-earth alloy until it loses its ability to stick to the large ceramic magnet. It will then fall away, and swing a few times as it cools. When it is cool enough to be magnetized again, it will rise and stick to the magnet, where the flame will again heat it up.
If the weight still touches the flame when it has fallen away from the magnet, adjust the pendulum's supports a little so that the weight rests a little farther away. If the weight is so far away that the magnet cannot pull it back up once it is magnetized, adjust the supports to bring it closer. Be careful when adjusting the supports, since they may be quite hot. Also be careful to move the candle so as not to burn yourself on the candle flame. When the engine is adjusted just right, it will settle down to a predictable swing, often taking only one swing to cool enough to stick to the magnet again. It will run as long as the candle burns.
If you have chosen to use the Canadian nickel, you will need a heat source better than the candle. A small alcohol lamp or fondue pot burner will do nicely. You may have to make the pendulum support wires longer to make room for the lamp.
S:sci-toys.com
We have all played with magnets. A pair of magnets by itself makes a wonderful toy. Today's magnets are even better than the best ones I remember playing with as a child. At toy stores and Radio Shack you can get flexible magnetic strips of plastic that can be cut into shapes with scissors. You can also get cheap and brittle ceramic magnets, stronger Alnico magnets, and even the new super strong rare-earth magnets. These are made of neodymium-iron-boron or samarium-cobalt, and are very powerful. At the end of this section I will list some sources I have found for good or cheap (or good and cheap) magnets. Some particularly nice tiny ones can be found in our catalog.
Through mail-order surplus houses you can get large neodymium-iron-boron magnets of incredible strength. For about five dollars each you can get magnets that will hold paperback books onto your refrigerator, or drag each other around a two-inch thick table, one on top of the table and one hidden underneath. I once entertained my guests and several waiters at a restaurant by mysteriously moving the stainless flatware around the table. People are not used to the effects of powerful magnets. They are amazed even when they can see what you are doing.
Because of their high strength-to-weight ratios, neodymium-iron-boron magnets seem to be little affected by gravity. Small ones can be placed on either side of a nose and will stay there until the wearer laughs so hard they slide upwards against gravity and snap together. Temporary earrings are also popular. Handle larger magnets with care, since they will pinch hard enough to cause blisters if they are separated only by small bits of skin. They are also easily capable of erasing the magnetically stored information on credit cards, computer floppy disks, and cassette tapes, so take care when selecting a pocket for them.
If you are showing magnets to a very young person for the first time, there are several tricks you will not want to forget. Use some large cheap ceramic magnets from Radio Shack or a toy store so they will not be easily lost or swallowed. Show how they attract and repel each other. At Radio Shack you can get some donut-shaped magnets that can slide over a pencil. The child can stack several so they each repel, forming a magic spring.
Actually the function generators are very versatile instruments as they are capable of producing a wide variety of waveforms and frequencies. In fact, each of the waveform they generate are particularly suitable for a different group of applications. The uses of sinusoidal outputs and square-wave outputs have already been described in the earlier Arts. The triangular-wave and sawtooth wave outputs of function generators are commonly used for those applications which need a signal that increases (or reduces) at a specific linear rate. They are also used in driving sweep oscillators in oscilloscopes and the X-axis of X-Y recorders.
Many function generators are also capable of generating two different waveforms simultaneously (from different output terminals, of course). This can be a useful feature when two generated signals are required for particular application. For instance, by providing a square wave for linearity measurements in an audio-system, a simultaneous sawtooth output may be used to drive the horizontal deflection amplifier of an oscilloscope, providing a visual display of the measurement result. For another example, a triangular-wave and a sine-wave of equal frequencies can be produced simultaneously. If the zero crossings of both the waves are made to occur at the same time, a linearly varying waveform is available which can be started at the point of zero phase of a sine-wave.
Another important feature of some function generators is their capability of phase-locking to an external signal source. One function generator may be used to phase lock a second function generator, and the two output signals can be displaced in phase by an adjustable amount. In addition, one function generator may be phase locked to a harmonic of the sine-wave of another function generator. By adjustment of the phase and the amplitude of the
harmonics, almost any waveform may be produced by the summation of the fundamental frequency generated by one function generator and the harmonic generated by the other function generator. The function generator can also be phase locked to an accurate frequency standard, and all its output waveforms will have the same frequency, stability, and accuracy as the standard.
The block diagram of a function generator is given in figure. In this instrument the frequency is controlled by varying the magnitude of current that drives the integrator. This instrument provides different types of waveforms (such as sinusoidal, triangular and square waves) as its output signal with a frequency range of 0.01 Hz to 100 kHz.
The frequency controlled voltage regulates two current supply sources. Current supply source 1 supplies constant current to the integrator whose output voltage rises linearly with time. An increase or decrease in the current increases or reduces the slope of the output voltage and thus controls the frequency.
The voltage comparator multivibrator changes state at a predetermined maximum level, of the integrator output voltage. This change cuts-off the current supply from supply source 1 and switches to the supply source 2. The current supply source 2 supplies a reverse current to the integrator so that its output drops linearly with time. When the output attains a predetermined level, the voltage comparator again changes state and switches on to the current supply source. The output of the integrator is a triangular wave whose frequency depends on the current supplied by the constant current supply sources. The comparator output provides a square wave of the same frequency as output. The resistance diode network changes the slope of the triangular wave as its amplitude changes and produces a sinusoidal wave with less than 1% distortion.
Analog Devices introduced the ADP2323, a 20-V, 3-A dual output DC-to-DC regulator featuring a high conversion efficiency of greater than 93 percent. The full featured ADP2323 regulator offers an input voltage supply range of 4.5 V to 20 V and an output range as low as 0.6 V up to 18 V at 1.5 percent voltage accuracy. With more design flexibility and configurability than other DC-to-DC regulators available today, the ADP2323 regulator can be easily configured to synchronise in an evenly phase-shifted topology or for dual-output (2 x 3A) or single interleaved output (up to 6 A). The ADP2323 provides accurate tracking capability between supplies and includes precision-enable input, voltage tracking input and POWER-GOOD features that allow a simple and reliable start-up sequence.
For power designers who need higher efficiency more design flexibility and configurability for multi-rail applications, the ADP2323 surpasses other available DC-to-DC regulators,” said Evaldo Miranda, product line director, Power Management Products Group, Analog Devices. “Unlike other regulators, the ADP2323 enables six output rails in an evenly phase-shifted topology, minimising input current ripple and system interference as well as a power saving mode and current sharing for higher output current capability.
The ADP2323’s switching frequency can be programmed between 250 kHz to 1.2 MHz or synchronised to an external clock to minimise interference in multi-rail applications. Both output channels run 180 degrees out of phase and can be synchronised to eliminate beat frequencies between regulators to minimise system noise. The regulator operates from input voltages of 4.5 V to 20 V and the output voltage can be as low as 0.6 V. The two PWM channels can be configured to deliver dual 3-A outputs or a parallel-to-single 6-A output. Designed for high efficiency for multi-rail applications, the ADP2323 operates over the −40 °C to +125 °C junction temperature range and is available in a compact 5 mm x 5 mm QFN-32 lead package.
Features
Applications
ZMD AG has announced availability of the ZLED7320, a new member of its high current ZLED7x20 family of 40V LED-Driver-ICs. The ZLED7320, which operates at up to 98% efficiency and is available in a small-footprint DFN-5 package, is designed to help manufacturer’s cost-effectively address the growing high-brightness (HB) LED lighting market.
“The ZLED7320 bridges the gap between our existing 0.75A and 1.2A high-efficiency drivers while the small-footprint package provides easier assembly” stated Dr. Hendrik Ahlendorf, Product Manager at ZMDI. “The ZLED7320 provides an ideal solution for many cost- and size- sensitive applications, including Retrofit LED lamps, signage, street and traffic lights, spotlights, appliance lighting and all types of general home and office illumination”.
The LED driver features on-chip switching transistor, 1200:1 dimming via PWM signal or fixed voltage, up to 1 amps of output current at +/- 3% accuracy and high-side current sensing. Built-in protection includes thermal shutdown, open-circuit and short-circuit protection. Due to its output current capabilities, the ZLED7320 supports the new high brightness and high current LEDs from major LED manufacturers without requiring an additional MOSFET to the application circuit. Only the addition of 4 passive components is required for a complete LED driver solution. The device operates at a temperature range of -40°C to 105°C.
The DFN-5 package simplifies board assembly and offers improved packing density for area- or volume- constrained systems. Thanks to its compact size, manufacturers can develop innovative new products and applications where efficient high-brightness LED solutions are a market advantage.
The ZLED7320 is in full production now and a complete evaluation kit is available from the company. For 2,500 pieces, the ZLED7320 is priced at 0.66€ or US$0.86.
ZMDI has also introduced the ZLED7330, a high-current 40V LED driver with user selectable switch dimming suitable for high brightness LED lighting applications and the ZLED7002, a dual channel LED Driver with supply voltage switchable channel toggling suitable for extended-life battery operated portable LED lighting applications. Both the ZLED7330 and the ZLED7002 are in full production and complete evaluation kits are available. For 2,500 pieces, the ZLED7330 is priced at 1.06€ or US$1.38 and the ZLED7002 is priced at 0.47€ or US$0.62.
Typical ZLED7x20 application circuit:
Central Semiconductor's CMPDM203NH (N-Channel) and CMPDM202PH (P-Channel) are Enhancement mode MOSFETs in industry standard SOT-23F packages that optimize high current capability and energy efficiency. The combination of high current, low gate charge and low on-resistance makes these devices the ideal selection for energy sensitive applications requiring higher drain currents.
Features
Applications
Benefits
Texas Instruments has introduced the industry's smallest, 16-bit delta-sigma analog-to-digital converter (ADC) with integrated programmable gain amplifier (PGA), reference, temperature sensor and 4-input multiplexer. Measuring 2 mm x 1.5 mm, the ADS1118 is more than 65-percent smaller than any other 16-bit ADC available today. The ADS1118 provides direct, linearized measurements with uncalibrated error guaranteed below 0.5 degrees Celsius (C) from 0 degrees C to 65 degrees C, a 75-percent improvement over the competition. It is also the lowest-power 16-bit ADC with a built-in internal reference supporting data rates up to 860 samples per second.
Key features and benefits of the ADS1118
Integration reduces overall solution size:
Integrates a 16-bit ADC, PGA, temperature sensor, low-drift reference and 4-input multiplexer for data acquisition of multiple signals from a wide variety of sensors.
Small size saves board space:
Small QFN package option enables close proximity to sensors, lowering component count by simplifying cold junction compensation for thermocouples.
Low power extends battery life:
Supports 2.0-V to 5.5-V power supplies while consuming only 150 uA (typical) to extend the battery life of portable, battery-powered industrial devices for temperature measurement, gas monitoring, industrial process control, instrumentation and more.
Provides a complete data acquisition solution when paired with an MSP430™ microcontroller.
Tools and support
TI offers a variety of tools and support to speed development with the ADS1118, including an IBIS model, anti-aliasing filter tool for data converters and op amp to ADC circuit topography calculator. Engineers can also ask questions and help solve problems in the Precision Data Converter Forum in the TI E2E™ Community.
An evaluation module (ADS1118EVM), including software and source code, is available today for a suggested retail price of $49.
Availability, packaging and pricing
The ADS1118 is available now in a 5-mm x 3-mm MSOP package. Samples of the 2-mm x 1.5-mm QFN package are also available today with production quantities expected in December. Both package options are priced at $2.22 in 1,000-unit quantities
SemiSouth Laboratories, Inc., the leading manufacturer of silicon carbide (SiC) transistor technology for high-power, high-efficiency, harsh-environment power management and conversion applications, has launched a new family of low cost SiC JFETs with very good linearity targeted at high-end audio applications.
SJEP120R100A and SJEP120R063A offer a very good linearity and best-in-class distortion. Compatible with standard gate driver ICs, both versions feature a positive temperature coefficient for ease of paralleling; extremely fast switching with no'tail' current at up to a maximum operating temperature of 150degC and a low RDS(on) max of 0.100Ω and 0.063Ω respectively. Devices are available in TO-247 packages; the 100mΩ part is also available in die form for integration into modules.
Comments Nelson Pass, founder of leading audio amplifier manufacturer Nelson Pass, Inc., "Over the last forty years I have greatly appreciated the qualities of lower power JFETs in audio circuits, and experimenting with the few examples of 'unobtainable' power JFETs has convinced me of their great potential. With the new SiC power JFETs from SemiSouth, this potential has been realized in reliable linear power amplifiers. In push-pull topologies, they exhibit a 50% to 70% improvement in distortion, and in single-ended circuits the improvement has been nearly ten-fold. Currently we profitably produce a small high-end audio amplifier using the SJEP120R100A devices and are engaged in developing other higher power amplifiers using this and the SJDP120R085 depletion mode devices."
Comments Dieter Liesabeths, SemiSouth's Vice President of Sales & Marketing, "These parts are especially suitable for high end audio amplifier designs which demand the best linearity performance and lower distortion. Compared to conventional SiC JFET for power applications, the prices for these audio parts has been reduced by about 15% in order to meet the demand of customers."
32-bit Microcontroller-based Dev Kit Provides Complete Solution for the Development of 24-bit Audio and Speech Applications With Record, Playback and Mixing Capabilities
Microchip Technology Inc., a leading provider of microcontroller, analog and Flash-IP solutions, today announced a 32-bit microcontroller (MCU)-based development kit for the creation of high-quality, 24-bit audio applications. The Audio Development Board for PIC32 MCUs features an 80 MIPS PIC32 MCU, a 24-bit Wolfson audio codec, a two-inch color LCD Display, a USB interface, and an onboard microphone. Supported by Microchip’s free software libraries, the kit provides a perfect solution for the development of speech and audio recording and playback products. Target applications include docks for portable audio players, home-entertainment systems and automotive sound systems.
The 80-MIPS PIC32MX795F512L MCU on the audio development board features 512 KB Flash and 128 KB RAM, providing plenty of processing power and memory to decode, analyze and play back audio and speech. Libraries are available for speech recording and playback, as well as MP3 music decoding applications. Additionally, an audio Sample Rate Conversion (SRC) library for33 kHz, 44.1 kHz and 48 kHz is also supported, which enables developers to reduce component costs for playback solutions. There are also libraries available for managing the USB interface and driving the on-board color LCD display, which features 16-bit color images. For those developers who are enrolled in the Apple Made For iPod (MFi) Licensing Program, the kit also interfaces to Microchip’s accessory development platform for iPod and iPhone.
“The Audio Development Board for PIC32 MCUs offers a complete platform that doesn’t break the budget for high-quality audio development,” said Sumit Mitra, vice president of Microchip’s High-Performance Microcontroller Division. “The board also includes an interface for use with our accessory development platform for iPod and iPhone, enabling expansion to support these popular devices.”
Packaging, Pricing & Availability
The Audio Development Board for PIC32 MCUs (part # DM320011) is available today, for $149.99 at microchipDIRECT (http://www.microchip.com/get/LJEC). For MFi licensees, the Digital Audio Development Kit for PIC32 MCUs (part # DM320411) adds the accessory development platform for iPod and iPhone. This kit will be available by September to MFi licensees via Apple's authorized distributor.
microchip.com
Based on organic materials, OLED displays have become an integral part of mobiles and smartphones, thanks to their superb brightness. Now, Electronic Assembly, a manufacturer of displays, has introduced the technology to industrial applications.
With an extremely high contrast ratio of 2000:1, the nine OLED models from ELECTRONIC ASSEMBLY are real eye-catchers. The high contrast ratio is achieved by using a genuinely black background and active display technology. A new, patented system eliminates the relatively short service life of previous OLED displays. OLED displays from Electronic Assembly can be operated 100,000 hours and more at room temperature. Even when used at maximum operating temperature (80°C), they retain 50 percent or their original brightness after 14,000 hours.
The OLED displays also provide full contrast at temperatures down to -40°C. No contrast adjustment is required for this. Their response time of 10 microseconds gives the displays an extremely fast response time as well, whether they are used at high or low temperatures. In addition, information shown on the OLED displays is easy to read, no matter what the viewing angle.
All major character sets – English, European, Japanese, and Cyrillic – are integrated in the alphanumeric displays and do not need to be created by the controller. Connection to the outside world is similar to the established HD44780 standard via 4 and 8-bit interfaces. Power is provided by a 3 or 5-volt single supply, whereby the brightest brightness is achieved with the 5-volt supply. Consumption ranges between 15 and 50 milliamperes, depending on the size of the display.
Electronic Assembly offers nine different organic displays. Colors include yellow or white, and the display area encompasses 2 rows with up to 8 characters each or 4 rows with up to 20 characters each, depending on the model.
lcd-module.com
IAR Systems announced that an IAR KickStart Kit for the LPC11U00 series of microcontrollers is now available. It is a low cost starter kit for evaluation and for designing and prototyping software applications. The kit includes an LPC11U14 evaluation board fitted with an LPC11U14 microcontroller, a USB connector, an LCD, and various other peripherals, a J-Link Lite debug probe, software tools, example projects and board support packages for various RTOSes.
The NXP LPC11U00 series of microcontrollers provides low cost 32-bit replacement for 8- and 16-bit microcontrollers in USB device applications. It features an integrated USB 2.0 full-speed device controller together with an ARM Cortex-M0 processor.
IAR KickStart Kit for LPC11U14 is prepared for use with IAR Embedded Workbench, the most widely used tool chain for ARM based microcontrollers recognized for its efficient code generation, comprehensive debugger, and user friendly IDE.
IAR KickStart Kit for LPC11U14 is in stock and available in IAR Systems’ e-shop. It is priced at EUR 129/USD 179. Part number is KSK-LPC11U14-JL.
iar.comAs explained earlier, the nanomaterials are lighter, stronger and long lasting than other materials. This advantage has been exercised in replacing the aluminium body of airplanes with composite materials including nanomaterials.
If the composite includes carbon nanotubes, the heat response of the material changes. A small electric current will cause a high increase in temperature of the nanotubes. Any internal damages will still change the heat flow, which can be picked up by the thermal camera.
If the experiment becomes a success, we can see airplanes that are made out of a whole new material with better performance and better safety.
The basic semiconductor manufacturing principle was used to manufacture such an agent. The research team included people from the Institute of Bioengineering and Nanotechnology and IBM.
