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Tester or Measurement (Instrument) Circuits

Test Equipment:  #'s - A        B - D        E - G
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Last Updated: October 24, 2017 02:55 PM
Circuits Designed by Dave Johnson, P.E. :

Honeybee Counter -  I designed a circuit similar to this one a long time ago to help a beekeeper count the number of bees going into or out of a hive.  The low power circuit uses a slotted opto-sensor to detect the passing bees.  The circuit advances an electronic counting. . . Circuit by David A. Johnson P.E.-July, 2000

Human Traffic Footstep Detector Preamp -  This circuit uses a surplus geophone to detect human footsteps from 100 feet away.  it was designed for monitoring the Mexico/USA border.  This preamp part of the system draws about 50 micro amps from a 12 volt supply. . . Circuit by David A. Johnson P.E.-July, 2006

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-368-7747


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Homemade Easter Egg Anemometer -  in any wind generator installation, it's critical to be able to measure wind speed.  That gives you a baseline against which to measure your machine's performance, and anemometers respond much more quickly to changes in wind speed than do wind generators.  Commercial anemometers  __ Contact OtherPower.com

Honeybee Counter -  I designed a circuit similar to this one a long time ago to help a beekeeper count the number of bees going into or out of a hive.  The low power circuit uses a slotted opto-sensor to detect the passing bees.  The circuit advances an electronic counting. . . Circuit by David A. Johnson P.E.-July, 2000

Hot Rodding a CDV700 Geiger Counter -  This project involves making several modification to an early 1960s era Victoreen CDV700 or CDV600-6B geiger counter.  These counters are available on E-Bay for around $50 to $100.  The modifications use modern electronic parts to improve the counter's stability, extend the run time, and add a solar recharging capability__ 

Hot Water Tank Indicator -  The idea for this project may have come to me in a flash of inspiration, and its a very simple way to check if a fuse has blown without removing it from its holder __ Designed by Andy Collison

Hot-Swap Structure Offers Improved Redundancy -  01/09/03 EDN Design Ideas:  For redundancy purposes, a number of power supplies, using ORing diodes, can work into the same load.  During maintenance, when you can remove any power supply, the minimum possible power perturbation at the load is desirable.  To compensate for the voltage drop across the ORing diodes, you must connect the power-supply feedback lines after the diodes, at the load __ Circuit Design by Samuel Kerem, Corvus Corp, Columbia, MD

How I Built a Wind Generator in My Backyard for $150. Part 1 -  I've been spending a great deal of time working on ways to generate my own electricity.  it isn't a necessity for me yet, but someday being electrically self-sufficient could really come in handy.  My interest started a __ Designed by Kevin Harris, Oklahoma Lately

How I Built a Wind Generator in My Backyard for $150. Part 2. -  Tools Required Surprisingly, building a simple wind generator only requires very basic hand tools, and if you are desperate you won't necessarily need all of them.  I used Jigsaw (or a hacksaw and a lot of determination) Drill (2) Drill Bits __ Designed by Radio LocMan

How I Built a Wind Generator in My Backyard for $150. Part 3 -  The next obstacle is building a hub to attach the blades to.  There are many types of ways that this can be done.  I have used circular sawblades and scrap steel disks.  I recommend the sawblade approach, as they are readily __ Designed by Hub Blade Assembly

How I home-built an electricity producing Wind turbine. Part 1 -  Several years ago I bought some remote property in Arizona.  I am an astronomer and wanted a place to practice my hobby far away from the sky-wrecking light pollution found near cities of any real size.  I found a great piece of property.   __ Designed by Mike Davis

How I home-built an electricity producing Wind turbine. Part 2 -  I managed to score one of the good 30 volt Ametek motors off of Ebay.  for only $26.  They don't go that cheap these days.  People are catching on to the fact that they make great wind generators.  Other brands will work, so don't fret about the price __ Designed by Radio LocMan

How I home-built an electricity producing Wind turbine. Part 3 -  Next I needed a mounting for the turbine.  Keeping it simple, I opted to just strap the motor to a piece of 2 X 4 wood.  The correct length of the wood was computed by the highly scientific method of picking the best looking piece of scrap 2 X 4 off __ Designed by Radio LocMan

How I home-built an electricity producing Wind turbine. Part 4 -  I never got a chance to properly test the unit before heading to Arizona.  One windy day though, I did take the head outside and hold it high up in the air above my head into the wind just to see if the blades would spin it as well as I had hoped.   __ Designed by Radio LocMan

How I home-built an electricity producing Wind turbine. Part 5 -  in operation, the wind turbine is connected to the controller.  Lines then run from the controller to the battery.  All loads are taken directly from the battery.  if the battery voltage drops below 11.9 volts, the controller switches the turbine __ Designed by Radio LocMan

How I home-built an electricity producing Wind turbine. Part 6 -  The first order of business was setting up and bracing the tower.  After arriving at my property and unloading my van, I drove to the nearest Home Depot (about 60 miles one way) and bought the 10 foot long piece of 1 1/4 inch conduit I needed for __ Designed by Radio LocMan

How I home-built an electricity producing Wind turbine. Part 7 -  This photo shows the controller, battery and associated electronics all wired up.  I have a 120V inverter connected to the battery and a multimeter to keep track of the battery voltage and wind turbine output voltage.  Also my electric shaver and __ Designed by Radio LocMan

How I home-built an electricity producing Wind turbine. Part 8 -  This web site has become very popular.  Thank you all for your interest and encouragement.  I am getting tons of email questions from people about all sorts wind power related (and not so related) issues.  Many are the same few questions asked over __ Designed by Radio LocMan

How I home-built an electricity producing Wind turbine. Part 9 -  UPDATE 05/17/07 Here is a photo of me setting up the wind turbine on my remote property during our May 2007 trip to Arizona.  I had left most of the equipment on-site in Arizona.  I only brought the turbine head and charge controller back home with __ Designed by Radio LocMan

How to Interpret DS1847/DS1848 Temperature Readings -  App Note 216: IC __ Maxim Integrated

How to Make a Q Meter -  This article appeared in the January/February issue of Amateur Radio (the journal of the Wireless institute of Australia) and is reprinted here for the convenience of others. (Aussies who are not members of the WiA are urged to join our new streamlined national body- it is the only way we have of defending our spectrum allocations against an increasingly greedy mixture of government and private enterprise). __ Designed by VK5JST / VK5TR

How to Make a Thermocouple Meter with the LTC2492 -  This video explains how to use the 24-bit LTC2492 2-channel delta-sigma analog-to-digital converter with Easy Drive input Current Cancellation to make thermocouple measurements.  The ADCs features and benefits are discussed, as is cold junction compensation; this is followed by a lab demonstration of the LTC2492 thermocouple __ Linear Technology/Analog Devices App Notes, Mark Thoren-Applications Engineering Manager-Mixed Signal Products Sep 15th 2008

How to Understand Non-Invasive Breath Analyzers -  Breath Analyzers are used to descry and quantify the alcohol content in the subject's breath non-invasively.  These are invented by Robert Frank Borkenstein.  These__ Dilin Anand

How to Use the MAXQ2000 as a Voltmeter -  App Note 4194-- 3/24/2008 -- (add 5/08) __ Maxim Integrated

HP-310 Wave Analyzer -  A summary of my HP-310, which I use as a VLF receiver __ Designed by Steve Hagerman

HP48SX IR DeCODER -  acsiI Drawing__ 

Human Traffic Footstep Detector Preamp -  This circuit uses a surplus geophone to detect human footsteps from 100 feet away.  it was designed for monitoring the Mexico/USA border.  This preamp part of the system draws about 50 micro amps from a 12 volt supply. . . Circuit by David A. Johnson P.E.-July, 2006

Human-Machine Interface through Electromyography -  Electromyography (EMG) is a technique of recording muscular activities by measuring the potential difference across a muscle of interest.  EMG signal acquisition is the latest trend as it paves way for...__ Electronics Projects for You

Humidity & Temperature Monitoring using Arduino with the IoT -  Using the internet of Things (ioT) in homes and industries it is possible to control any electrical or electronic equipment.  Moreover, you can get the information from any sensor and analyse...__ Electronics Projects for You

Humidity Detector -  This humidity sensor consists of 2 copper conductors that are located at small distance from each other.  The relay switches as soon as the moisture makes a connection that is more or less electrically conductive between the 2 electrodes.  How does the humidity detector works? When the electrical resistance between the 2 sensors __ Designed by Popescu Marian

Humidity Indicator & Controller -  Presented here is a simple humidity indicator and controller.  in industries such as textile, the change in moisture content has a direct impact on the properties of fabric, such as tensile...__ Electronics Projects for You

Humidty Sensor to Data Aquisition System Interface -  The circuit shown in the schematic features zero drift operational amplifiers (LTC1250 and LTC1050) and a precision instrumentation switched capacitor block (LTC1043).  This design will maintain excellent DC accuracy down to microvolt levels.  This method was chosen over the use of a true RMS-to-DC or log converter because of __ Linear Technology/Analog Devices App Note, Mar 16th 2010

Hybrid vacuum tube/solid-state audio power Amplifier -  08/11/14  EDN Design Ideas:  An audio power amp design that combines vacuum tube input circuitry with solid-state output and feedback components. __ Circuit Design by Craig D. Merz

Hygrometer & hygrostat -  A simple handheld relative humidity meter, complete with settable control output. __ Designed by Manfred Mornhinweg

Hygrometer WiFi ESP8266-Arduino -  This device is digital wifI hygrometer.  it's a miniature arduino web server.   By mapping ports of your router, you can connect to it from anywhere on the world.  This hygrometer uses arduino skech and trendy vector graphics format SVG. __ Designed by © Pavel Janko

Hygrometer WiFi ESP8266-Lua -  This hygrometer is digital wifI hygrometer.  it's a miniature web server.
By mapping ports of your router, you can connect to it from anywhere on the world.  This hygrometer uses Lua software and
trendy vector graphics format SVG.  Hygrometer is quite fast and stabil. __ Designed by © Pavel Janko

Hyper-Simple Battery Capacity Tester -  The circuit described here is eminently suitable to indicate the capacity of a battery.  We use a cheap electric clock for this.  By connecting a resistor across the battery terminals, the battery is discharged somewhat faster than with the clock alone.  if we pick a resistor with a value of 5.6R, the discharge current amounts__ 

IC & DMM form direct-read-out temperature probe -  09/01/06 EDN Design Ideas:  Simple circuit yields linear voltage-versus-temperature output __ Circuit Design by Alfredo H Saab and Bich Pham, Maxim Integrated Products Inc, Sunnyvale CA

IC 555 Timer Tester -  This simple and easy-to-use gadget not only tests the IC 555 timer in all its basic configurations but also tests the functionality of each pin of the timer.  Once a timer...__ Electronics Projects for You

IC Diodes Help Deduce Junction Temperature -  07/07/94 EDN Design Ideas:  A simple method for directly measuring an IC 's temperature uses the device's input-protection diodes as temperature sensors.  Static-discharge protection diodes are common features in many modern IC input structures, and their location on the IC makes them ideal as noninvasive temperature sensors __ Circuit Design by Edward S Brinkman, Cincinnati Electronics Corp, Mason, OH

IC Forms Precision Triangular-Wave Generator -  04/08/10 EDN Design Ideas:  Generate a triangular wave for testing other circuits.   __ Circuit Design by Akshay Bhat, Maxim Integrated Products Inc, Sunnyvale, CA

IC removes nonlinear temperature effects -  09/25/03 EDN Design Ideas:  A common technique for removing nonlinear temperature-related effects from a dc voltage is to incorporate a temperature sensor that a microprocessor samples via an A/D converter.  The processor determines—by mathematical calculation or a temperature-indexed look-up table—the amount of adjustment is necessary at a given temperature and delivers the resulting value via a D/A converter __ Circuit Design by Kevin Schemansky, Maxim Integrated Products, Howell, MI

IC Testers-Analogue & Digital -  This unusual design works on the assumption that most IC failures are caused by the PN junctions at their inputs and outputs.  in testing these, it does not need any circuitry or test configurability to determine the correct operation of the IC 's functions, instead simply providing indication on LEDs of the PN junction characteristics of each pin.  For digital ICs  the failure of an LED to light for a pin will usually indicate a failed PN junction there.  Linear ICs  may give more complex readings when in good condition, so a known good IC of the same model and manufacturer must first be inserted, and its reading compared to the suspect IC manually to observe any differences. __ Designed by Kevin Koster

ICL7107-DigitAL LED VOLTMETER -  This digital voltmeter is ideal to use for measuring the output voltage of your DC power supply.  it includes a 3.5-digit LED display with a negative voltage indicator.  it measures DC voltages from 0 to 199.9V with a resolution of 0.1V.  __ 

IF for TV-Tuner for Spectrum Analyzers-AA4FB -  Schematic only __ Designed by va3iul

Implement a clip-detection for BTL Class D Amplifiers -  5-Mar-09 EDN Design Ideas:  An external clip-detection circuit adds a useful feature to some Class D IC amplifiers __ Circuit Design by Dimitri Danyuk and Rich Lenser, Niles Audio, Miami, FL

Implement an audio-frequency tilt-equalizer filter -  EDN Design Ideas:  02/02/2012    Developing the transfer functions lets you customize the filter __ Circuit Design by Francesco Balena, Electro-Acoustic Design, Conselve  PD, Italy

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Test Equipment:  #'s - A        B - D        E - G
H - L        M - O        P - S        T - Z

 


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