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Electronic Design: 1980, pp 166 and 400 Ideas For Design, Vol 4, 1980 pp 8, Hayden Book Co. "BIFET Op-Amp and bipolar Op-Amp join forces for low drift and fast slewing" Modern application of the classic Goldberg composite amplifier.
EDN: January 5, 1980, pp 166 "Op-Amp Pair forms unity-gain buffer" Presents a high-performance non-inverting offset nulled composite amplifier.
Electronic Design: January 7, 1982, pp 291-300 "Program analyzes six-element active RC networks" HP-41C application to find poles/zeros and produce Bode plots of active networks that contain a single Op-Amp and multiple RC feedback.
Electronic Design: February 18, 1982, pp 203 "Compensator cancels cold-junction errors" A circuit is described that uses a single LM-10 Op-Amp to scale and provide for thermocouple cold junction compensation. Voted best of issue
EDN: May 12, 1982, contributed circuit pp 172-174 "Great Gator Giveaway - Winning MUX applications" Presented a video speed Multiplying DAC design using high speed MUX's and GHz Op-Amps. Voted first place in the Harris analog design contest
Electronic Design: March 31, 1982, pp 105-110 "Program quickly figures complex filter parameters" An HP-41C application that when given low, high or band-pass filter design goals will prescribe high-pass and low-pass pole locations to meet the goals. The resulting filter can be realized with active or passive filter sections.
EDN: January 20, 1983, pp 188 "DC/DC converter powers EEPROM's" Presents a single IC DC/DC converter that will meet Intel EEPROM specifications while working off of an existing 5 Volt bus. Voted best of issue
Power Sources Conference, presented 1984 and 1985 "Modular DC/DC Converter Users Guide" Conference paper describing uses and DC and high frequency measurement techniques as applied to modular DC/DC converters. (plagiarized once now!)
Motorola Application Note: AN920A, contributed circuit on page 27 "Theory and applications of the uA78S40 switching regulator" Describes an Intel EEPROM programming source using the uA78S40 IC.
POWERTECHNIQUES: February 1987, pp 32-37 DC/DC Converter Serves Diverse Distributed Power Needs" Describes the CALEX 45 watt, single output family of DC/DC converters. Outlines design features and applications.
EDN: June 11, 1987, pp 205 "DC/DC converter adds power to existing bus" Describes a circuit to add more power to a 5 Volt power bus. Circuit use's another existing supply voltage with excess capacity and a DC/DC converter.
CADALYST: Vol 5, NO 6, pp 48-50 "Tailoring AutoCAD: Making Shapes" Describes the thought and coding/compilation process used to define AutoCAD shape files for any custom application.
Personal Engineering & Instrumentation News: September 1988, pp 61-72 "Menu/shape system speeds schematic entry with AutoCAD" Describes a complete ready to use schematic capture system for use with AutoCAD. Provides complete design information along with shape and menu files.
EDN: September 29, 1988, pp 173-182 "Spice techniques facilitate analysis of feedback circuits" Describes how to make loop measurements on active feedback circuits using SPICE's ideal voltage and current sources. Overcomes limitations and extends previous methods, resulting in faster computation and smaller net-lists. Describes key concepts of feedback in detail.
CADALYST: November, 1988, pp 28-30 "Tailoring AutoCAD: Screen Menus" Describes in detail how to create custom AutoCAD pull-down menus for user specific applications.
Electronic Design: November 23, 1988, pp 123-126 and December 14, 1989, pp 88. "Test DC/DC Converters With Isolated Load" Describes a MOSFET, fully floating, 50 Watt load that is used when testing power supplies. Discusses sources of error when making measurements and how the load overcomes some of these errors. Voted best of issue
EDN: November 24, 1988, pp 225 "JFET doubles opto-isolators bandwidth" Describes the limitations of opto isolators when used in feedback circuits. Presents simple cascode circuits that doubles the bandwidth of existing designs by adding one JFET.
EDN: May 11, 1989, pp 197 (Also published in Electronics-World + Wireless-World: Feb, 1992) "Amplitude-locked loop speeds filter test" The circuit presented facilitates hands off automatic measurement of a low pass filters cutoff frequency. Voted best of issue
IEEE: Circuits and Devices Magazine, July 1989, pp 54-55 "Use Modern SPICE Techniques to Analyze Feedback Circuits" Describes how to make loop measurements on active feedback circuits using SPICE's ideal voltage and current sources. Overcomes limitations and extends previous methods, resulting in faster computation and smaller net-lists.
EDN: September 1, 1989, pp 117-124 "Proper Output Decoupling Maximizes Power-Supply Operation" Discusses the dynamic nature (with frequency) of power supply output impedance that all power supplies have. Describes the potentially devastating effects of adding bypass capacitors to the output of a power supply when the output impedance is unknown. Proposes measurement techniques and proper bypassing methods.
EDN: September 14, 1989, pp 163-164 "Spice Model Handles Linear Optocouplers" Presents a linearized SPICE model for optocouplers. Model includes input diode characteristics and output transistor capacitances. If the model is developed for a given operating point very accurate results can be obtained.
EDN: March 15, 1990, pp 180-181 "Spice models 3-terminal reference" Presents a SPICE macromodel of the TL431 voltage reference. The model is accurate for most simulations, contains only one transistor, has no convergence problems and speeds simulation time by at least a factor of 3.
Electronic Design: March 22, 1990, pp 106 "Rid Measurements Of Supply Noise" Describes a simple rechargeable/isolated power supply based on NICAD's to supply +/-15 volt power to noise sensitive circuits. Optically coupled power MOSFETs isolate the NICAD charger during measurements for high isolation, low capacitance and low noise.
Power Conversion and Intelligent Motion: April 1990, pp 13-24, May 1990 pp 47-50 "Behavioral Modeling and PSpice Simulate SMPS Control Loops" Behavioral models are applied to switching regulators to produce large signal models that accurately simulate all input and output characteristics. The models cover voltage mode, feed forward mode, and current mode. Emphasis on simulation accuracy and avoiding convergence problems.
EDN: May 24, 1990, pp 173 "Peak detector holds signals indefinitely" Describes a peak detector - infinite hold circuit that was designed for fast peak charging NICAD batteries. The circuit uses a Ramp-up D/A technique to capture the peak voltage.
Personal Engineering & Instrumentation News: October 1990, pp 49-56 "Powerful circuit-analysis programs eliminate need for preproduction runs" Describes the application of Monte-Carlo and Worst Case analysis techniques to find worst case circuit performance. Describes in detail component modeling and the functional differences between Monte-Carlo and Worst Case analysis types. Examples are provided using PSpice as a circuit simulator.
Personal Engineering & Instrumentation News: December 1990, pp 65-66 "PC-based power-supply tester slashes setup time to minutes" A write-up of the "PC/Workbench" personal power supply tester that was developed at CALEX to provide automated ATE performance at an engineers desk. Describes hardware configuration, design goals and constraints.
EDN: December 20, 1990, pp 154-156 "Spectrum analyzer speeds RMS measurements" How to use a spectrum analyzer to make wideband rms voltage measurements on complex waveforms. Especially useful in finding the true heating effect in capacitors, resistors and transistors.
Personal Engineering & Instrumentation News: 1991-1992 Served as design automation contributing editor for PE&IN for two years. Wrote 12 columns dealing with selecting EDA tools, Making EDA work, EDA management and reviewed SPICE and AutoCAD tools and techniques.
Electronic Design: May 9, 1991, pp 117&120 "Keep Spice Accuracy Above 1 MHz" Presents simple macromodels for common 1/4W resistors and 0.1" L.S. ceramic capacitors that accurately model these components parasitic components up to 1 GHz. These models greatly improve the accuracy of simulations that exceed 1 MHz or transient time steps of less than 1 uS.
Electronic Design: March 5, 1992, pp 78 "IC Eases Monitoring of DC/DC Converters" Designed a simple undervoltage lockout and overtemperature function using one IC that is useful in DC/DC converter circuits.
EDN: May 7, 1992, pp 220 "Spice Models Solar Array" Complete design equations are given to model a solar panel with Spice. Four simple measurements are made on the solar array for a complete Spice model.
Power Conversion and Intelligent Motion: September 1992, pp 46-52 "Mixed-Mode Simulator Analyzes Switching Supplies" The PSpice Mixed-Mode simulator is applied to the complete simulation of SMPS power conversion circuits. By modeling the PWM control chip as a mostly digital device a very fast cycle by cycle simulation can be done Goes into detail on how to model SMPS chips and getting the simulations to run reliably and quickly.
MicroSim Newsletter: October 1992 "Mixed Analog/Digital Simulation Using PSpice" Gives detailed examples on getting started using the digital simulation capabilities of PSpice. Explains startup conditions, interfacing to analog circuits and modeling new logic families.
CADS (German): January 1993 "Simulation von gemischten Analog/Digitalsystemen" German version of MicroSim application note, first published in October 1992.
EDN: May 27, 1993, pp 150 "Program Generates Noise Sources" Called an "Outstanding Visual Basic Program" by the editors of EDN this program will make PWL random noise sources for PSpice from your parameters. Calculates and makes models in seconds. Gives noise bandwidth and slewrate of resulting circuit. A professional application.
MicroSim Corp. Newsletter, October 1993, pp 1 & 3-6 "Create Analog Random Noise Generators for PSpice Simulation" Reprint of entire text from EDN synopsis above. Program was placed on MicroSim BBS for MicroSim customers to download. A very popular program and add-on for PSpice.
Electrical Design & Mfg.: Sept/Oct 1993, pp4 "DC/DC Converters Don't Overspecify" A one page synopsis of the most common ways that users of DC/DC converters can add unnecessary cost to their circuits that use DC/DC converters. Covers applying the input and output circuits.
EDN: Oct 28, 1993, pp 117-132 "Simple PSpice models let you simulate common battery types" A unified approach to modeling most common battery types is presented. Included are Lead Acid, Nickel Cadmium and Alkaline types. This article is a first as no unified SPICE models exist for batteries in the public domain. The use of these models can change a 200+ hour laboratory exercise to a 1 minute computer run.
PC TECHNIQUES: Feb/Mar, 1994, pp 44-46 "Get That Diskette's Number" Describes an assembly language subroutine callable from C that will read the volume serial number from a MSDOS 4.0 and latter formatted disk. Provides a complete assembly listing and C test program.
Personal Engineering: March 1994, pp 35-38 "Accurate Transformer Simulation Requires Measuring Key Parameters" Describes how to apply SPICE's built in "Mutual Coupling" transformer model to real world transformer simulations. Also describes PSpice enhancements to the standard SPICE transformer model.
EDN: March 3, 1994, pp 96 "Notebook power supply has two outputs" Describes in detail how to add a simple -24 volt LCD bias output to any forward type of converter. Complete design is given for a 6-12 volt input, 5 volt @ 1.5 amp and -24 volt @ 10 mA power supply that might be used in a notebook computer or similar battery operated computer system.
MicroSim Corp. Newsletter, April 1994, pp 8-12 "Improve Simulation Accuracy When Using Passive Components" Covers how to model common resistors and capacitors for temperature and frequency dependence. 1/4 Watt Film and SMT resistors along with leaded and SMT ceramic capacitors are discussed.
PC TECHNIQUES: Apr/May, 1994, pp 84-86 "Exposing the Stealthy Vector-Grabber" Describes a C language program that will log interrupt-vector usage on a program by program basis. This is useful in determining if any TSR's could possibly be interfering with other programs. Also let's TSR developers make sure that their TSR's are working correctly and uninstalling properly.
EDN: March 31, 1994, pp 59-60 "Low-cost converter drives fluorescent tubes" Presents a CCFT Tube driver that can be built for less than $3.00. The simple 3 transistor circuit can drive 1/2" by 8" small tubes at 30 kHz. The input range is 10-20 volts DC. Efficiency is high as total input current is less than 200 mA. Voted best of issue
MicroSim Corp. Newsletter, July 1994, pp 8-12 "Model Transient Voltage Suppressor Diodes" TVS Diodes present modeling challenges to the PSpice user. These diodes are unlike zeners due to their high power ratings. A complete electrical and thermal model is presented for popular 500 and 1500 watt devices.
EDN: October 13, 1994, pp 84 "Serial-Controlled "postage-stamp" computer governs process" Details the construction and use of a 16 channel to 1 precision analog multiplexer originally designed for ATE equipment. The Basic Stamp computer takes a serial command to change the mux channel. This easy to build system costs about $100 and compares to systems that cost over $1000. Voted best of issue
Electronics Products & Technology: October 1994, pp 84 "Tips on using DC/DC converters" Reviews the most common user problems and mistakes in applying PCB mount DC/DC converters. Reviews how to properly add filtering and thermal design considerations.
MicroSim Corp. Newsletter, January 1995, pp 1,8-11 "Use Ferrite Bead Models to Analyze EMI Suppression" Presents the first universal behavioral models (backed up by actual measurements!) for Ferrite beads. Beads are widely used for EMI suppression in high speed systems. Until now circuits that used these EMI prevention techniques could not be simulated. The Bead models take into account the bead material, size of the bead, number of turns and bias current and accurately predict the frequency response of the bead in circuit.
EDN: February 2, 1995, pp 99 "PSpice models nickel-metal-hydride cells" An accurate PSpice model is shown that correctly models the discharge of NiMh batteries. The model allows designers the possibility of running discharge simulations in software for the first time. The model was developed with actual discharge data, not manufacturers literature, hence the high accuracy.
EDN: May 11, 1995, pp 144 "Single IC adds analog inputs to digital PLC" Shows how to use the single chip RISC Microprocessor from Microchip Technology to add 4 analog inputs to any all digital Programmable Logic Controller (PLC). The uP is commanded to read any of 4 input channels then it outputs the resulting A/D code as a series of pulses to the PLC's counter so the PLC can read the result. The number of pulses vary from 0-255 representing the analog input over a range of 0-5 volts.
Personal Engineering & Instrumentation News: June 1995, pp 50-53 "Models update SPICE to simulate new technologies, circuit types" Reviews what can be done with SPICE today. Such as simulating batteries, ferrite beads, PCB analysis checking, etc. Also covers the finer points of modeling passive components for RF frequency effects.
Electronics Specifier: October 1995, Cover, pp 22-23 "Specifying Power Sources" Covers common sense "Team Design" of power supplies. Although common sense, the steps outlined are not commonly done. To be a true partner in power system design the entire design and manufacturing team must be willing to partake in the specification process and review milestones on the go to produce the best products in record time.
EDN: December 7, 1995, pp 175-181 "Design guidelines help dc/dc converters work properly over long lines" A common problem in using dc/dc converters in widely distributed systems is how to design the system with respect to the input resistance that the converter will see. The article shows that the common practice of trying to increase the input voltage range to greater than 2:1 is fruitless because of the maximum power theorem.
EDN: August 1, 1996, pp 110-113 "Build your own superhetrodyne receiver" Details the design of a 3 IC short wave radio. The radio covers the 4.5 to 10 MHz band where plenty of international broadcasters reside. The design includes an RF preselector and ceramic IF interstage filter. Based on a 3 pin Plessy IF amp / AM detector IC to reduce parts count. Voted best of issue
EDN: March 27, 1997, pp 81-83 "Drive high-voltage varactor diodes from just 5V" Shows a clever way to get 20 volts of drive for a varactor diode from a 5 volt only supply system by using optoelectric devices.
EDN: April 24, 1997, pp 80-81 "Circuit tricks increase LCD contrast" LCD modules are typically used in single supply embedded projects and they require a negative LCD bias voltage to achieve maximum contrast. The circuits presented, show simple ways of generating the negative bias by charge-pumping a uP clock, "stealing" power from a RS232 driver chip and "stealing" negative bias from the RS232 connection directly.
EDN: July 17, 1997, pp 112-113 "Opamp makes precise 9V battery splitter" Describes a circuit to derive a precision 5 volt supply and -4 volt supply from a standard 9 volt battery. Uses a linear Op-Amp and a precision reference. This circuit is linear, not switching or charge pump. Voted best of issue
EDN: September 25, 1997, pp 170-172 "Single chip builds tiny aircraft receiver" Why waste time in airports working? Instead build this simple, single chip aircraft band radio and listen in! The unique part of this circuit is that it uses the Received Signal Strength Indicator (RSSI) of a Philips NE605 as an AM demodulator. Voted best of issue (and plagiarized twice now - it's very popular!)
EDN: December 18, 1997 pp 102-103 "Metal detector uses single IC" A simple "beat frequency" type of metal detector is described. The design is based on the LM389 audio amplifier IC using two of the uncommitted transistors as the search and beat oscillators. Voted best of issue (and plagiarized once now!)
QST: January (Part I) and February (Part II), 1998 (QST Cover Project) "Build your own network analyzer" Using IC's made for the wireless industry I described the hardware and software for a network analyzer that can be built for personal use. The frequency range is 10 Hz to 16 MHz with a dynamic range of 50-60 dB. The analyzer is run from a PC via the RS232 port. A complete Visual Basic control program was also presented. Reprints of the article are available from the ARRL.
QST: February 1999 (QST Cover Project) "A Synthesized 2 Meter FM Receiver with PC Control" Built using commonly available IC's this receiver is fully microprocessor controlled. As an added feature the receiver can be connected to a PC for full computer control. Under PC control the receiver can band scan, do a memory scan and even display a spectrum of the 2 meter band. Reprints of the article are available from the ARRL.
QST: March 1999 "PIC Development on a Shoestring" Chronicles my approach to making PIC microprocessor projects come alive using low cost tools. Includes sections on selecting PIC's, Writing code in high level languages, Debugging using RS232 and including LCD displays in your projects. Reprints of the article are available from the ARRL.
EDN: May 27, 1999, pp 104-106 "Use derivatives to catch RF calibration errors" Describes a method that looks at the time rate of change of a power versus frequency curve instead of just the curve alone. This shows up things like pinched RF cables and power holes in an easy to see format, whereas with the use of straight power versus frequency curve, power holes are easily missed during testing of RF components or systems.
EDN: July 22, 1999, pp 130-132 "Simple Technique Speeds Microstrip Breadboarding" The title pretty much captures the idea here. By using sheared strips of RT/Duroid PC material and gluing them to regular FR4 copper clad the development time for making 50 ohm RF circuits can be greatly reduced. Additionally the Duroid material, since it is Teflon based may be bent conform to whatever shape is needed for the breadboard. Voted best of issue
QEX: January 2000 (QEX Cover Project) "Build this 2-250 MHz VHF Source" Article describes a hetrodyned VHF source architecture that provides up to +17 dBm output over a frequency range of 2-250 MHz. The design includes a fast RS232 port for computer control with the capability to have up to four sources 'linked' on one RS232 port. A PC control program is included along with an ActiveX control to allow nearly any Windows application to control the source. Reprints of the article are available from the ARRL.
EDN: May 25, 2000, pp 122 "ActiveX control brings bit manipulation to Windows" I developed this ActiveX control to allow fast 'C' like bit functions to be used with languages like Visual Basic. All the basic get/set bit and shift functions are included (14 in all). Any Windows language or application that can use ActiveX technology can use this simple but useful control.
QEX: January 2001, pp 52-57 "Build a data acquisition system for your computer" Introduces the low cost PIC DAS (PIC16C63 Based Data Acquisition System). The PIC DAS is a self contained Data Acquisition system powered by a PIC Microprocessor. The PIC DAS reads simple ASCII commands from a PC's RS232 port to control it's 8 bit digital I/O port, 8 channel A/D and 4 channel D/A converters. Also included is full software support for nearly any computer that can talk to a serial port and any DOS or Windows application. Reprints of the article are available from the ARRL.
"Program predicts VSWR-mismatch RF uncertainties" Hewlett-Packard (now Agilent Technologies) once offered a useful little cardboard slide rule for calculating the uncertainty in RF measurements stemming from VSWR (voltage-standing-wave-ratio) mismatch. Unfortunately, this handy device is no longer available. A Visual Basic program accomplishes the same function on a PC with the added feature of being able to cut and paste the result, something that the cardboard calculator could not do. Voted best of issue
EDN: Nov 22, 2001 "Simple Circuit Forms Peak/Clipping Indicator" A simple stereo peak detector is presented that is suitable for inclusion in multimedia PC audio applications. The circuit has easily understood adjustments for gain, attack and delay times.
EDN: Dec 20, 2001 "Analog input circuit serves any microcontroller" This simple A/D converter that can be used with any microprocessor only uses 5 parts and can be built for less than 50 cents. The circuit is based on a simple ramp type architecture, which gives reasonable 5% kind of accuracy. For many types of "human feedback" the accuracy is more than sufficient especially since the cost is roughly 1/2 of an integrated circuit A/D converter.
QEX: March 2002, pp 3-10 "Build a 250 MHz Network Analyzer" The article shows how to add 8 IC's to the VHF source project (QEX January 2000) to build a true Reflection / Transmission Network Analyzer. The analyzer is built the same as a commercial design and utilizes a full one port / transmission calibration routine for outstanding accuracy and performance. The heart of the design is the AD8307 log amp from analog devices. Reprints of the article are available from the ARRL.
"Impedance / Frequency Scaling" I get questions all the time asking: "How do I change this receiver for that band?" or "How do I change that filter from x MHz to Y MHz?". This brief application note reviews the procedures to 'Tweak' circuits from one frequency or application to another. Includes a design spreadsheet to speed the calculations and most importantly - what to watch out for.
Circuit Cellar Ink: January 2004, PP16-25 "Build an inexpensive temperature-testing chamber" This project was originally conceived as a way to have a small temperature testing chamber on an engineers bench without the expense of buying a larger than needed commercial unit. The idea of using a Peltier device to make a small chamber was in my head for several years - this project came to fruition when a small commercial car travel cooler came on the market. I added a PIC microcontroller, LCD display, RS232 interface and some power relays - and I was in business!
EDN: February 25, 2004 "Simple technique makes low cost PCB shields" Describes the process involved to use a small, low cost die-cast aluminum (or zinc) project box as a very effective RF shield. Pictures show how to layout the ground tracks on the PCB and how to assemble the project box over the PCB. Since the box has considerable mass it can also be used as a local heatsink for voltage regulators, etc. This technique was developed for the HF synthesizer project shown in the projects section of this website.
QST: June, 2004, PP28-34 "Give That Drake Receiver a New Lease on Life" Modernize that great old Drake R-4 (A, B or C) or SPR-4 series receiver with a PIC controlled synthesizer that gives full 1.5 - 30 MHz receive capability without the need for extra crystals. This project is a modernized Drake FS-4 with a PIC controlled synthesizer, modern VFD display and many operational features that the FS-4 did not have. Now you can receive every HF band without the need to shop on ebay for crystals! Reprints of the article are available from the ARRL.
"Squegging - What the heck is that?" I have received many questions about what "squegging" is - In this application note, I go over some common forms of squegging that I know about.
EDN: July 21, 2005, PP70-71 "High Impedance FET Probe Extends RF-Spectrum Analyzers Usable Range" Basically how to make a 1 Megaohm probe for a 50 ohm spectrum analyzer that has a gain of 1. A useful circuit if you want to use your 50 ohm spectrum analyzer to probe high impedance circuits.
EDN: August 18, 2005, PP84-85 "Frequency Dithering Enhances High-Performance ADCs" Adding noise (i.e. Dithering) is all the rage with ADCs now a days. Most implementations use random voltage addition to the ADCs input to dither the ADC. The circuit described uses a random frequency modulation and constant amplitude dither which has some advantages, especially in FFT applications.
Circuit Cellar Ink: December 2005 "LAN Based Data Acquisition system" Describes a Data Acquisition system with 8 channels of 12 bit analog I/O (Analog input and Analog Output) and 16 channels of Digital I/O that is fully controllable via a 10/100 Ethernet (LAN) connection. The system talks via an embedded terminal interface program and can serve up web pages and send emails all via the TCIP protocol. LAN is a very versatile platform for these kinds of applications as the unit can be programmed anywhere in the world and is not limited to a cable directly connect to the users PC.
EDN: March 30, 2006 "Single switch serves dual duty in small, microprocessor-based system" Ever wonder how to allow a small hand held uP system to be turned on with a pushbutton switch, then be able to turn itself off? If so then this simple two transistor design is for you. A single pushbutton turns on the uP and also allows another function to be implemented like changing display modes. Then when the uP is done whatever task it was doing it can turn itself off. This simple design idea solves this age old problem.
EDN, March 1, 2007 "Digital-I/O circuit adapts to many interface voltages" Faced with the task of designing a universal test fixture that would work with many different logic levels, this circuit makes use of a 256-tap digital potentiometer to set the interface's voltage via an adjustable regulator between 2.5V and 5V. Kind of a "poor man's" programmable pin driver.
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