Open-Source Hardware for the Efficient Economy

In the open-source hardware development and distribution model, designs are created collaboratively and published openly. This enables anyone to study, modify, improve, and produce the design—for one’s own use or for sale. Open-source hardware gives users full control over the products they use while unleashing innovation—compared to the limits of proprietary research and development.

This practice is transforming passive consumers of “black box” technologies into a new breed of user-producers. For consumers, open-source hardware translates into better products at a lower cost, while providing more relevant, directly applicable solutions compared to a one-size-fits-all approach. For producers, it means lower barriers to entry and a consequent democratization of production. The bottom line is a more efficient economy—one that bypasses the artificial scarcity created by exclusive rights—and instead focuses on better and faster development of appropriate technologies.

Open-source hardware is less than a decade old. It started as an informal practice in the early 2000s with fragmented cells of developers sharing instructions for producing physical objects in the spirit of open-source software. It has now become a movement with a recognized definition, specific licenses, an annual conference, and several organizations to support open practices. The expansion of open-source hardware is also visible in a proliferation of open-source plans for making just about anything, from 3-D printers, microcontrollers, and scientific equipment, to industrial machines, cars, tractors, and solar-power generators.

As the movement takes shape, the next major milestone is the development of standards for efficient development and quality documentation. The aim here is to deliver on the potential of open-source products to meet or exceed industry standards—at a much lower cost—while scaling the impact of collaborative development practices.

The Internet brought about the information revolution, but an accompanying revolution in open-source product development has yet to happen. The major blocks are the absence of uniform standards for design, documentation, and development process; accessible collaborative design platforms (CAD); and a unifying set of interface standards for module-based design—such that electronics, mechanical devices, controllers, power units, and many other types of modules could easily interface with one another.

Can unleashed collaboration catapult open-source hardware from its current multimillion dollar scale to the next trillion dollar economy?

One of the most promising scenarios for the future of open source hardware is a global supply chain made up of thousands of interlinked organizations in which collaboration and complementarity are the norm. In this scenario, producers at all levels—from hobbyists to commercial manufacturers—have access to transparent fabrication tools, and digital plans circulate freely, enabling them to build on each other quickly and efficiently.

The true game changers are the fabrication machines that transform designs into objects. While equipment such as laser cutters, CNC machine tools, and 3-D printers has been around for decades, the breakthrough comes from the drastically reduced cost and increased access to these tools. For example, online factories enable anyone to upload a design and receive the material object in the mail a few days later. A proliferation of open-source digital fabrication tools, hackerspaces, membership-based shops, fab labs, micro factories, and other collaborative production facilities are drastically increasing access and reducing the cost of production. It has become commonplace for a novice to gain ready access to state-of-art productive power.

On the design side, it’s now possible for 70 engineers to work in parallel with a collaborative CAD package to design the airplane wing for a Boeing 767 in 1 hour. This is a real-world proof of concept of taking development to warp speed—though achieved with proprietary tools and highly paid engineers. With a widely available, open-source collaborative CAD package and digital libraries of design for customization, it would be possible for even a novice to create advanced machines—and for a large group of novices to create advanced machines at warp speed. Complex devices, such as cars, can be modeled with an inviting set of Lego-like building blocks in a module-based CAD package. Thereafter, CNC equipment can be used to produce these designs from off-the-shelf parts and locally available materials. Efficient industrial production could soon be at anyone’s fingertips.

Sharing instructions for making things is not a novel idea. However, the formal establishment of an open-source approach to the development and production of critical technologies is a disruptive force. The potential lies in the emergence of many significant and scalable enterprises built on top of this model. If such entities collaborate openly, it becomes possible to unleash the efficiency of global development based on free information flows. This implies a shift from “business as usual” to an efficient economy in which environmental and social justice are part of the equation.

 

Catarina Mota is a New York City-based Portuguese maker and open-source advocate who cofounded the openMaterials (openMaterials.org) research project, which is focused on open-source and DIY experimentation with smart materials. She is both a PhD candidate at FCSHUNL and a visiting scholar at NYU, and she has taught workshops on topics such as hi-tech materials and simple circuitry. Catarina is a fellow of the National Science and Technology Foundation of Portugal, co-chair of the Open Hardware Summit, a TEDGlobal 2012 fellow, and member of NYC Resistor.

Marcin Jakubowski graduated from Princeton and earned a PhD Fusion Physics from the University of Wisconsin. In 2003 Marcin founded the Open Source Ecology (OpenSourceEcology.org) network of engineers, farmers, and supporters. The group is working on the Global Village Construction Set (GVCS), which is an open-source, DIY toolset of 50 different industrial machines intended for the construction of a modern civilization (http://vimeo.com/16106427).

This essay appears in Circuit Cellar 271, February 2013.

RL78 Challenge Winner’s Workspace in Lewisville, TX

Lewisville, TX-based electrical engineer Michael Hamilton has been a busy man. During the past 10 years, he created two companies: A&D Technologies, which supplies wireless temperature and humidity controllers, and Point & Track, which provides data-gathering apps and other business intelligence tools. And in his spare time, he designed a cloud electrofusion machine for welding 0.5″ to 2″ polyethylene fittings. It  won Second Prize in the 2012 Renesas RL78 Green Energy Challenge.

In an interview slated for publication in Circuit Cellar 273 (April 2013), Hamilton describes some of his projects, shares details about his first microcontroller design, and more.

Michael Hamilton in his workspace. Check out the CNC machine and 3-D printer.

During the interview process, he also provided a details about his workspace, in which he has a variety of interesting tools ranging from a CNC machine to a MakerBot 3-D printer. Hamilton said:

I have a three-axis CNC machine and MakerBot 3-D printer. I use the CNC machine to cut out enclosures and the 3-D printer to create bezels for LCDs and also to create 3-D prototypes. These machines are extremely useful if you need to make any precise cuts or if you want to create 3-D models of future products.

Hamilton also noted:

I recently purchased a Rigol Technologies DSA-815-TG spectrum analyzer. This device is a must-have, right behind the oscilloscope. It enables you to see all the noise/interference present in a PCB design and also test it for EMI issues.

Michael Hamilton’s test bench and DSA815

He has a completely separate area for PCB work.

A separate space for PCB projects

Overall, this is an excellent setup. Hamilton clearly has a nice collection must-have EE tools and test equipment, as well as a handy CNC machine and decent desktop storage system. The separate PCB bench is a great feature that helps keep the space orderly and clean.

As for the 3-D printer, well, it’s awesome.

New Products: March 2013

Universal PCB Test System

SaeligThe ABI BoardMaster 8000 PLUS is a versatile, self-contained, and easy-to-use PCB test system. The system, which is manufactured by ABI Electronics, comprises a comprehensive set of test instruments, including a built-in PC, for testing and faultfinding on almost any type of PCB.

The BoardMaster 8000 PLUS test system is well suited for applications including telecommunications, transportation, and automotive manufacturing. The system is used by land, air, and naval forces to provide on-site test and repair.

The BoardMaster 8000 PLUS is an integrated package of high-specification instrumentation controlled by sophisticated but easy-to-use software. The hardware is installed in a rugged transportable case that also contains a high-specification Windows PC. The BoardMaster 8000 PLUS is based on a modular, customizable system. Its software can be configured to guide users step-by-step through a test procedure with custom-annotated picture images, instructions, and attached datasheets to provide quick Pass/Fail results.

A typical BoardMaster 8000 PLUS configuration includes two board fault locator modules, with 128 test channels for multiple test methods for fault diagnosis and functional testing of digital ICs, IC connections status, voltage acquisition, and V-I curve testing of components on unpowered boards. The PCB test system also includes an analog IC tester for in-circuit functional testing of analog ICs and discrete components (i.e., no programming or circuit diagrams needed) and a fully configurable V-I tester for detection of faults on unpowered boards.

The BoardMaster 8000 PLUS test system features a multiple instrument station with eight high-specification test and measurement instruments in one compact module (frequency counter, digital storage oscilloscope, function generator, digital floating multimeter, auxiliary PSU, and universal I/O) and a triple-output variable power supply that provides required supply voltages to the unit under test.

Contact Saelig for pricing.

Saelig Co., Inc.
www.saelig.com

ABI Electronics, Ltd.
www.abielectronics.com


Small, Low-Cost Antenna

The compact MicroSplatch embedded antenna utilizes Linx Technologies’s simulation tools and provides performance similar to the standard Splatch antenna while only utilizing one third of the circuit board’s space.

The MicroSplatch is reflow-compatible and capable of withstanding oven temperatures up to 260°C. The antenna is available in 2.4-GHz and 403-, 418-, 433-, 868-, and 916-MHz bands. The antenna is well suited for remote controls, pagers, and compact data transmission devices.

The MicroSplatch antenna can be easily added to your design. You simply need a footprint for the antenna and an associated proximity ground plane.

The affordable MicroSplatch antenna is priced for cost-sensitive applications. Contact Linx for pricing.

Linx Technologies
www.linxtechnologies.com


FEM for Smart Energy/Advanced Metering Infrastructure & ISM Band Applications

The RFFM6403 is a highly-integrated front-end module (FEM) for smart energy/advanced metering infrastructure (AMI) applications. The single-chip RFFM6403 FEM reduces customer design time and speeds customer time-to-market for portable battery-powered equipment, general 433-/470-MHz ISM-band systems, and smart energy/AMI applications operating in the 405-to-475-MHz frequency range.

The feature-rich RFFM6403 integrates a transmit high-power path with a 30.5-dBm PA and Tx harmonic output filtering a transmit bypass through path with Tx harmonic output filtering, and a receive path with a low-noise amplifier (LNA) with bypass mode. The FEM also features a low insertion loss/high-isolation SP3T switch and separate Rx/Tx 50-Ω ports, which simplifies matching and provides input and output signals for both the Tx and Rx paths.

The RFFM6403 is designed for AMI systems operating with high-efficiency requirements and a minimum output power of 30 dBm. In the receive path, the Rx chain provides 16 dB of typical gain with only 5 mA of current and a 1.7-dB noise figure. The FEM’s small form factor (6 mm × 6 mm × 1 mm) minimizes product footprint and reduces the external component count and associated assembly costs.

Contact RF Micro Devices for pricing.

RF Micro Devices, Inc.
www.rfmd.com


Compact Buck Converter for High-Voltage Applications

The LTC3646 is a 40-V input synchronous buck converter capable of delivering up to 1 A of continuous output current from a 3-mm × 4-mm DFN-14 (or thermally enhanced MSOP16) package. The converter operates from a 4-to-40-V input voltage range. It is well suited for automotive and industrial applications requiring high-voltage input capability, high efficiency, and fast switching frequencies for small-solution footprints.

The LTC3646 utilizes controlled on-time architecture capable of stepping inputs as high as 36 V down to 3.3 V. It features switching frequencies in excess of 2 MHz, which keeps switching noise out of critical frequency bands (e.g., AM radio). The converter can deliver fast transient response, even with duty cycles less than 10%. Its internal synchronous rectification delivers efficiencies as high as 95% and requires only 140 µA of quiescent current, which maximizes battery run time.

The LTC3646’s internal switching frequency can be programmed between 200 kHz and 3 MHz or synchronized to an external clock. The combination of high efficiency and only 140 µA of quiescent current offers high efficiency over a broad load range. For noise-sensitive applications, the LTC3646 can be used in forced continuous operation to minimize voltage ripple.

The standard LTC3646 offers a 2-to-30-V output range. The LTC3646-1 offers a 0.6-to-15-V output range. Both versions feature internal soft-start, internal or external compensation, and robust short-circuit protection.

Pricing for the LTC3646EDE/-1 and LTC3646EMSE/-1 starts at $2.85 each in 1,000-unit quantities. Pricing for the extended-temperature (I grade) versions (i.e., the LTC3646IDE/-1 and LTC3646IMSE/-1) starts at $3.14 each in 1,000-unit quantities. Pricing for the high-temperature (H grade) options (i.e., the LTC3646HDE/-1 and LTC3646HMSE/-1) starts at $3.39 each in 1,000-piece quantities.

Linear Technology Corp.
www.linear.com


Four-Quadrant PWM Servo Controller

The ESCON 36/3 EC is a four-quadrant PWM servo controller capable of controlling brushless DC motors with Hall sensors up to approximately 100 W. It features a digital current controller with a large bandwidth for optimal motor current/torque control and drift-free speed, which enables a 0-to-150,000-rpm speed range. The ESCON 36/3 EC features fully configurable digital and analog inputs and outputs and can run in various operating modes including speed controller (closed and open loop) and current controller.

The compact servo controller is controlled by an analog set value. This value can be specified by analog voltage, an external or internal potentiometer, a defined value, or a PWM signal with a variable duty cycle. The controller can enable or disable the power stage depending on the rotation’s direction, or it can use speed ramps for acceleration and deceleration. Hall sensors can be used to regulate the speed.

When the servo controller is connected to a PC via a USB port, it can be easily configured with the “ESCON Studio” graphical user interface (GUI). You can use a variety of functions during startup and while configuring the inputs and outputs, monitoring, data recording, and diagnostics. Assistance is provided by user-friendly software wizards and an automatic procedure for fine tuning the controller is also available.

The ESCON 36/3 EC features circuits that protect against overcurrent, excess temperature, under- and over-voltage, voltage transients, and short circuits in the motor cable. It is equipped with protected digital inputs and outputs and an adjustable current limitation to protect the motor and the load. The analog output voltage can be used to monitor the motor current and the motor shaft’s actual speed. The large range for the input voltage and the operating temperature enables the ESCON 36/3 EC to be used in a variety of drive applications.

Contact maxon for pricing.

maxon motor
www.maxonmotorusa.com


Modules Provide Flexible & Practical Digital I/O Functionality

The USB-7230 and USB-7250 isolated USB digital I/O modules are designed for I/O expansion or portable applications. Each module features a high-speed frequency/event counter, a digital filter, and change of state (COS) detection in a single USB module that supports high-voltage control and monitoring applications’ flexibility and reliability requirements.

The USB-7230 provides 32-channel isolated digital I/O and two-channel frequency/event counters. The USB-7250 provides eight-channel solid-state relay output (four-form C and four-form A), eight-channel isolated digital input, and two-channel frequency/

event counters. The modules feature high-voltage on/off control and monitoring and isolation voltage support up to 2,500 VRMS. They also include integrated frequency/event counting and COS detection via the built-in complex programmable logic device (CPLD). A programmable digital filter removes unexpected glitches from input channels to efficiently monitor the I/O status.

The USB-7230 and USB-7250 modules feature USB power, removable screw-down terminals for simplified connection, and multifunctional stands for fast and easy desktop-, rail-, or wall-mounting. They also include lockable USB cables to secure connectivity. The USB modules simplify device ID settings with a rotary control that identifies the active module in multiple-connection configurations.

The USB-7230 and USB-7250 modules include ADLINK’s U-Test application, which is a free, ready-to-use testing program that delivers out-of-the-box configuration and generates simple functions to get the platform up and running. With U-Test, no programming is required for full data monitoring, logging, and FFT analysis. As with all ADLINK USB digital I/O devices, the USB-7230 and USB-7250 are compatible with National Instruments’s LabVIEWTM, MathWorks’s MATLAB, and Microsoft Visual Studio and Visual Studio.NET.

Contact ADLINK for pricing.

ADLINK Technology, Inc.
www.adlinktech.com


High-Efficiency Stepper Motor Driver IC

The LV8702V is a stepper motor driver integrated circuit (IC) designed to reduce overall power consumption. The motor driver also helps reduce heat generation, vibration, and noise from motors in office automation equipment applications (e.g., copiers, scanners, and multifunction printers).

The stepper motor driver IC uses driver waveform monitoring to detect motor conditions. It reduces power consumption by automatically reducing the current value according to the rotation speed or motor load. The stepper motor has a 9-to-32-V operating voltage range. Protection features include output short protection, a thermal shutdown function, and a step-out detection function. The LV8702V’s advanced functions include stall detection, step-loss, and current drive optimization.

The LV8702V is available in a 5.6-mm × 15-mm SSOP44J package. The motor costs $6 per unit in 2,000-quantity units.

ON Semiconductor
www.onsemi.com


Pressure Sensors for Flow Measurement in Bypass Configuration

The SDP601 and SDP611 sensors are differential pressure sensors specifically calibrated to measure mass flow in a bypass configuration. A bypass configuration is well suited for applications where individually adapted flow channels are necessary or where small differential pressures must be measured with high precision (e.g., HVAC applications, which often involve large flow volume measurement).

Bypass configurations use an orifice or a linear-flow restrictor to generate a differential pressure in a flow channel. This pressure is measured over the orifice or the linear flow component. The difference between the pressures before and after the orifice correlates to the volumetric flow in the channel, depending on the specific characteristics of the flow restriction component. Therefore, the mass flow can be calculated from the measured pressure drop (i.e., differential pressure) over the orifice.

The SDP601 and SDP611 sensors expand Sensirion’s product range of digital differential pressure sensors in the SDP600 series. Along with the other products in this series, these sensors provide a digital I2C output and are fully calibrated and temperature compensated. Like all devices in the SDP600 series, the SDP6x1 sensors are available in two versions. The SDP601 is designed for direct threaded connection to a pressure manifold with O-ring sealing. The SDP611 is designed for tube connection.

Contact Sensirion for pricing.

Sensirion
www.sensirion.com


Single-Board Retrocomputer

The CGCOLORMAX is a single-board retrocomputer that supports add-on Arduino Shields and runs a modern implementation of the BASIC programming language. The board has connections for color video (i.e., video graphics array) output and a PS/2 keyboard input. An SD card socket on the front of the board provides the “floppy drive” for program and data storage.

A stereo music synthesizer, an Arduino Shield interface, and a battery-backed clock are included on The CGCOLORMAX. Hardware interfacing is available as 20 I/O lines on the rear connector and 20 lines on the Arduino Shield connector. This versatile design enables you to easily interface to serial, SPI, I2C, 1-wire, and other circuits.

The CGCOLORMAX also includes a bootloader that enables firmware updating and comes preloaded with BASIC. The board can be tethered to a PC/Mac via a USB cable and programmed via a serial terminal. The USB connection can also provide power to the board.

The CGCOLORMAX can operate as a stand-alone computer by supporting a keyboard and a VGA monitor. The board can be powered by any 8-to-18-V AC or DC power supply. The default BASIC program can be automatically loaded from internal or SD card memory.

Contact CircuitGizmos for pricing.

CircuitGizmos, LLC
www.circuitgizmos.com


Optimized Compiler with Advanced Debug Capabilities

A complete integration with the Eclipse IDE—IAR Systems’s integrated development environment (IDE)—is available for IAR Embedded Workbench for ARM, the high-performance development tool suite. With this integration, IAR offers Eclipse support as an alternative to the IAR Embedded Workbench IDE, which enables its customers to use its build tools and debugger within the Eclipse IDE.

While the proprietary IAR Embedded Workbench IDE is tailor-made for embedded development, intuitive, and easy-to-use, the open-source Eclipse IDE provides flexibility through its extensible framework and its ability to interoperate with a large ecosystem of supplementary tools.

The full integration of the IAR C-SPY debugger replaces the GDB-based debugger that is standard with Eclipse, and enables IAR Systems’ debug technology to be fully exploited from within the Eclipse IDE. C-SPY’s debug functionality includes a timeline window that graphically correlates visualizations of interrupt logs, data logs, power samples, and user-defined events plotted against time. C-SPY supports ARM’s Embedded Trace Macrocell (ETM) and its Embedded Trace Buffer (ETB). Power profiling enables fine-tuning of an application’s power consumption, and the C-SPY Trace window displays detailed trace data.

In addition to all standard Eclipse CDT (C/C++ development tooling) functionality, the integration enables additional features (e.g., project import functionality, stepping on function call level, and complex code and data breakpoints).

Contact IAR for pricing.

IAR Systems
www.iar.com


Advanced Video Annotation Controller

The eVAC2000 is a real-time NTSC/PAL video overlay and video annotation controller for the PCI/104 bus. The controller features a high-resolution graphics accelerator, a digital NTSC/PAL TV decoder, a digital NTSC/PAL TV encoder, and a video overlay controller, which are all contained within a single PC104 card. The eVAC2000 is well suited for applications requiring titles, dynamic grids, or visible watermarking.

The eVAC2000 accepts up to four composite NTSC or PAL analog video inputs, from inputs including video cameras, digital video recording equipment, and video instrumentation. It is capable of mixing video and graphics data or mixing two separate video channels, and can provide output to drive a video graphics array (VGA) monitor, a TV monitor, or a TMDS/LVDS flat-panel display. The eVAC2000 video annotation controller features multi-format, alpha-blending, hardware-enabling graphics/video and video/video to be alpha-blended over gradations from transparent to fully opaque.

The high-throughput, low-latency controller uses a high-performance, 64-bit, 2-D graphics accelerator combined with an 8-Mb frame buffer to deliver rapid video graphics processing. It has a –40°C to 85°C operating temperature and a single 5-V power requirement.

The eVAC2000 is supported by a comprehensive software development kit (SDK) for Windows, Linux and QNX that provides a high level API to configure and control the embedded video hardware (via more than 500 internal registers). The SDK includes support libraries and drivers and a range of example applications (including source code).

Contact Advanced Micro Peripherals for pricing.

Advanced Micro Peripherals, Ltd.
www.ampltd.com

 

Issue 272: EQ Answers

The answers to the Circuit Cellar 272 Engineering Quotient are now available. The problems and answers are listed below.

Problem 1—Why does the power dissipation of a Darlington transistor tend to be higher than that of a single bipolar transistor in switching applications?

Answer 1—In switching applications, a single transistor can saturate, resulting in a low VCE of 0.3 to 0.4 V. However, in a Darlington pair, the output transistor is prevented from saturating by the negative feedback provided by the driver transistor. If the collector voltage drops below the sum of the VBE of the output transistor (about 0.7 V) and the VCE(sat) of the driver transistor (about 0.3 V), the drive current to the output transistor is reduced, preventing it from going into saturation itself. Therefore, the effective VCE(sat) of the Darlington pair is 1 V or more, resulting in much higher dissipation at a given current level.

Problem 2—Suppose you have some 3-bit data, say, grayscale values for which 000 = black and 111 = white. You have a display device that takes 8-bit data, and you want to extend the bit width of your data to match.

If you just pad the data with zeros, you get the value 11100000 for white, which is not full white for the 8-bit display—that would be 11111111. What can you do?

Answer 2—One clever trick is to repeat the bits you have as many times as necessary to fill the output field width. For example, if the 3-bit input value is ABC, the output value would be ABCABCAB. This produces the following mapping, which interpolates nicely between full black and full white (see Table 1). Note that this mapping preserves the original bits; if you want to go back to the 3-bit representation, just take the MSBs and you have the original data.

3-bit INPUT 8-bit OUTPUT
000 00000000
001 00100100
010 01001001
011 01101101
100 10010010
101 10110110
110 11011011
111 11111111

Problem 3—Can an induction motor (e.g., squirrel-cage type) be used as a generator?

Answer 3—Believe it or not, yes it can.

An induction motor has no electrical connections to the rotor; instead, a magnetic field is induced into the rotor by the stator. The motor runs slightly slower than “synchronous” speed—typically 1725 or 3450 rpm when on 60 Hz power.

If the motor is provided with a capacitive load, is driven at slightly higher than synchronous speed (1875 or 3750 rpm), and has enough residual magnetism in the rotor to get itself going, it will generate power up to approximately its rating as a motor. The reactive current of the load capacitor keeps the rotor energized in much the same way as when it is operating as a motor.

See www.qsl.net/ns8o/Induction_Generator.html for additional details.

Problem 4—In Figure 1, why does this reconstruction of a 20-kHz sinewave sampled at 44.1 kHz show ripple in its amplitude?

Answer 4—The actual sampled data, represented by the square dots in the diagram, contains equal levels of Fsignal (the sine wave) and Fsample-Fsignal (one of the aliases of the sinewave). Any reconstruction filter is going to have difficulty passing the one and eliminating the other, so you inevitably get some of the alias signal, which, when added to the desired signal, produces the “modulation” you see.

In the case of a software display of a waveform on a computer screen (e.g., such as you might see in software used to edit audio recordings), they’re probably using an FIR low-pass filter (sin(x)/x coefficients) windowed to some finite length. A shorter window gives faster drawing times, so they’re making a tradeoff between visual fidelity and interactive performance. The windowing makes the filter somewhat less than brick-wall, so you get the leakage of the alias and the modulation.

In the case of a real audio D/A converter, even with oversampling you can’t get perfect stopband attenuation (and you must always do at least some of the filtering in the analog domain), so once again you see the leakage and modulation.

In this example, Fsignal = 0.9×Fnyquist, so Falias = 1.1×Fnyquist and Falias/Fsignal = 1.22. To eliminate the visible artifacts, the reconstruction filter would need to have a slope of about 60dB over this frequency span, or about 200 dB/octave.

Electrical Engineer Crossword (Issue 272)

The answers to Circuit Cellar’s March electronics engineering crossword puzzle are now available.

Across

1.     JACOBSLADDER—Climbing arc [two words]

5.     WOZNIAK—Apple I

8.     SPARKCOIL—Uses a low-voltage DC supply to create high-voltage pulses

10.   JITTER—Creates an imperfect timing signal

11.   ERG—Energy measurement

13.   ACOUSTICOHM—Equivalent to µbar s/cm3 [two words]

15.   BUFFER—Provides electrical isolation

16.   WIFI—Provides movement to smartphones, PCs, and tablets

17.   POSIX—An IEEE operating system compatibility standard

18.   PEAKTOPEAK—Alterations between high and low values

19.   MUTEX—Capable of ensuring atomic access to any shared resource

20.   NAKAMURA—University of California, Santa Barbara professor credited with inventing the blue LED

 

Down

2.     OSCILLATOR—American physicist George W. Pierce (1872–1956); piezoelectric

3.     EIGENTONE—A pitch capable of resonance

4.     FRETSONFIRE—Open-source gameplay for music lovers [three words]

6.     NEGATIVEFEEDBACK—Type of amplifier invented in 1927 by Harold Black [two words]

7.     BAFFLE—Sound wave obstruction

9.     MORSECODE—A pre-texting means of communication [two words]

12.   COMBFILTER—Capable of causing delay [two words]

14.   CHIPSET—Intel created the first family of these