John Wiltrout's Blog

  • Experimenting with an Isotek Kelvin Resistor

    jw0752
    Today I salvaged out a circuit board from an ESPE Dental Cure light. To my delight there was Kelvin precision resistor on the board. Specifically it was an Isotek PBV R033 which is a heat sink mounted 10 Watt Kelvin resistor with a value of 0.033 Ohm...

  • Identifying the Triplets in a Power Supply Front End

    jw0752
    There are three components routinely used in the power input section of many linear and switching power supply that have confused me over the years and have often been difficult to identify. In this blog I would like to call your attention to them, s...

  • Reverse Engineering integral DC Converters

    jw0752
    The other day while trouble shooting a control panel from a Pelton Crane Delta Q Dental Sterilizer I noticed that two of the required voltages were not being supplied by the main power supply but were instead being synthesized by a small group of com...

  • Shop Tips - Bread Boarding Resistors

    jw0752
    In the process of salvaging components from circuit boards a lot of perfectly good resistors with short leads are obtained.  In this Shop Tips I am going to demonstrate my process for turning some of these resistors into excellent plug in a...

  • Satellite Signal Attenuation

    jw0752
    Today we had a snow storm in our area.   Pretty isn't it? Unfortunately it also has to be shoveled off the driveway. While this is not one of my favorite activities to do, it is not the worst side effect of the snow. The worst side...

  • Playing with an OP 191 Op Amp

    jw0752
    One of the really great things about the E-14 Web Site is how much one can learn just by reading and paying attention to some of the threads. On Jan 9th posted information on the OP191 and OP192 Op Amps which he likes to use in his des...

  • Building an LED Amplifier for Mom

    jw0752
         This is the first time that I have encountered the concept of 'LED Amplifier'. I did not even know what it was until the situation presented itself and I knew that it was what I needed to solve the latest challenge from my Mo...

  • Christmas Vacation Project - A Power Supply for Grandson Ivan

    jw0752
    Nine year old grandson, Ivan, and I had two projects on the schedule for his Christmas Vacation. The first was to build a special Solder Iron Modification, See: Solder Iron for Ivan with a built in TimeoutWith the solder iron complete our plan was to...

  • Exploring LMD18200 3A H-Bridge

    jw0752
    The other day I came across this interesting circuit board from a piece of Medical Equipment. My interest was immediately caught by the LMD 18200 H-Bridges in the upper left corner. I checked the part number out on Newark's site to see if they were s...

  • Repairing a Dental X-Ray Control

    jw0752
    Tonight I am going to perform a simple repair on a 70 KVp 7 mA Dental X-Ray control, Model 770 made by Gendex Corp in November 1997. This x-ray unit was one of the best designed of the all the units I have worked on over the years. The fact that afte...

  • Solder Iron for Ivan with a built in Timeout

    jw0752
         Ever since I helped Grandson Ivan, age 9, with his school Science Project, See Grandson, Ivan, and the Volcano Science Project , I have continued to feed his curiosity and enthusiasm for electronics. So far, in addition to th...

  • Experimenting with LT 3080 Low Drop Out (LDO) Voltage Regulator

    jw0752
    In Chapter 9 of Art of Electronics,3rd Ed. Horowitz and Hill discuss the LT 3080 LDO Voltage Regulator. This component caught my interest and so I ordered two of them for the purpose of experimentation and familiarization.   http://www.newark.co...

  • Dental Sterilizer Power Supply Board Repair

    jw0752
    Tonight I have been involved in the diagnosis and repair of a Hybrid Switching/Linear power supply board from a Pelton Crane Validator Plus dental instrument sterilizer. Due to a design flaw in this model sterilizer this is not the first time I have ...

  • Nominal VS Actual Power of USB Power Pack

    jw0752
    The other day I was reading a blog by raspjoenoob   about trying to run a Raspberry Pi with a USB Power Pack.   USB POWER BANK // PORTABLE POWER SUPPLY  Later the same day I was in Walmart where I noticed they had 2200 mAh Po...

  • Pulse Width Modulation Test Jig

    jw0752
         It isn't uncommon for me to find myself in need of a Pulse Width Modulation (PWM) signal in some of my bench experiments. Up until now I have put together a breadboarded PWM generator and modified it to suit my needs. The...

  • Different Approach to Art & Electronics

    jw0752
    Quite a while ago I blogged about this Tectrol 1 kilowatt power supply that I obtained from a piece of medical equipment.   Thing of Beauty Since then I have tried to think of a use and also tried to sell it on Ebay all to no avail. Once ag...

  • Shop Tips - Bread Board Voltmeter

    jw0752
    There are many times, when I am working on an experiment or project using my bread board, that I want to monitor the voltage at different points in the circuit. This usually involves setting up a couple DVMs and running test clips into the proper pos...

  • I Want to Do Electronics!  Where do I start?

    jw0752
    This is one of the most common introductions that we find from new visitors to the Element 14 web site. Inspirational programs like Ben Heck, Instructables, and many others are doing a good job of catching people's attention and interest. With ea...

  • Face to Face with Tektronix on Tour

    jw0752
    Back in the first part of September I was seeking to improve my knowledge of modern and upscale Oscilloscopes. On the Tektronix web site I found a couple of excellent downloads. One was titled "ABCs of Probes" and the second was titled "XYZs of Oscil...

  • Grandson, Ivan, and the Volcano Science Project

    jw0752
    Earlier this summer my grandson, Ivan, a serious 8 year old, asked me if I would help him with a science project for school. Ivan and I have been working together from time to time on small electronic projects and when he comes to visit I try to send...

  • Salvaging a CFL - Hidden Treasure

    jw0752
    Everyone is familiar with the Compact Fluorescent Light or CFL. Since they appeared on the scene they have invaded our homes and pushed the poor old incandescent bulb nearly to extinction. Most of the CFLs that I have purchased had 5 year guarantees ...

  • Repairing a Cadco Dry Processor II

    jw0752
    I have spent the last 30 years repairing the electro-mechanical equipment that is used by Dentists to repair and replace teeth. While I am officially retired at this time this doesn't stop my sons Mike and Matt, who currently own and run the comp...

  • Salvage and Exploration of a MC14541 Timer IC

    jw0752
    One of my favorite activities is salvaging electronic parts from old equipment. I am always in search of interesting components so that I can take the process one step further and explore, experiment and learn. This time I was taking apart a Com...

  • A Visit to DAB

    jw0752
    This week a detour from our vacation route allowed Millie and I to pay a visit to DAB and his lovely wife. I had hoped to meet DAB in person so that I could learn a little more from this multifaceted man. DAB is an accomplished author of several very...

  • Shop Tips - Meter Stand

    jw0752
    While nearly all of my handheld meters have a built in, hinged, panel in the back that can be used as a stand I have never been happy with the stability of these panels. There are several handheld meters, in the shop, that have been designated as &qu...