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John Wiltrout's Blog

164 posts
Recently I was working on a bread board circuit provided by jc2048 . One of the things that I find very convenient when wiring up a bread board are short wires with an alligator clip on one end and a bread board pin on the other. I use these cables to hook up peripheral meters, sensors, and actuators to the bread board circuit. In the past I have taken cheap alligator to alligator jumper cables, cut them in half and just added a bread board pin to the cut end. While this works the cables do not ...
I recently bought a power control module from a Chinese source. All I needed to do was provide the input power, up to 75 volts at 12 Amps and the module would allow me to output a digitally controlled voltage or current up to 60 Volts and 12 Amps. I will not go into the assembly of the unit as I have perhaps done one too many power supply builds in my blog already.   I had on the shelf a perfect candidate for an enclosure for this unit. It was really heavy duty with an already available fu ...
jw0752

Walking in the Dark

Posted by jw0752 Top Member Aug 1, 2019
One of the things that I like to do each day is go for a nice long walk. What makes me a little unusual is that I like to do it at night when it is quiet and dark. I typically leave the house about 11 PM and walk for about an hour and a half. My routes vary from night to night but I am most often on sidewalks or on the roadway when there are no sidewalks. Last night as I walked through a particularly dark section of town I caught my boot toe on a piece of raised sidewalk that was not visible in ...
jw0752

Strain Relief Extractor

Posted by jw0752 Top Member Jul 2, 2019
If you do any service work on electrical or electronic devices you have undoubtedly run into strain reliefs on power or control cords that had to be removed and replaced.     I have found these devices very frustrating. They are made of a very tough, slippery plastic. To remove them they must be compressed and then pulled from the hole where the cord goes through the chassis. Most of the time the pliers slips from the grip. If I am lucky I do not pinch myself but almost always the r ...
Several weeks ago I purchased a couple of Modules that were advertised as able to provide 1 Hz to 150 kHz signal with a 0% to 100% duty cycle control.     The modules were able to be powered with 3 volts to 30 volts and would output a signal of this same magnitude. The output was rated at 5mA to 30mA depending on the supply voltage. The accuracy of the device at 2% for the Frequency and 1% for the Duty Cycle is acceptable for the type of experiments that I do in my lab.   ...
It is always hard for me to not be amazed by the technological progress that has been made in the last 50 or so years. The other day I came across an unusual motorized switch that was made for Western Electric by Raymond Controls Corp. It is a KS-19175-L1 Interrupter. Since Western Electric was the manufacturing arm of the Bell System my first thoughts were that this unique device was part of a telephone system and a little research confirmed this. Here are a couple pictures of the device:   ...
       Since I do a lot of circuit board salvage I end up with a good supply of great components with short leads. When I use these components in my experiments and builds I must either deal with the short leads or add an extension. This is usually done by tinning the component lead and the extension and then holding them parallel while heating the solder and allowing it to bridge them. This works fine but there is always the danger when soldering the component to t ...
A week or so ago I wrote a short blog about a variable AC isolated bench power supply that I wanted to build. See the following Blog:   An Extreme Ripple Power Supply Build   The idea was just a seed and a pile of assorted resources. Just as I hoped, four of my friends here on element 14 stepped up and gave me some great advice and collaboration on the build. I want to specially thank: genebren , lui_gough , three-phase , and jc2048 without whose suggestions and ideas I could not h ...
I usually like to build my projects before I blog about them. This is probably due to the number of times the initial plans do not lead me down the envisioned path. The simplicity of this build along with a good pile of solid resources and the fact that I must wait for my panel meters to arrive has made me decide to blog a preview.   In my shop almost never a week goes by with out the need of an AC voltage source. I use the AC source to test motors, lights, power supplies, and circuit boar ...
In honor of tariq.ahmad 's emphasis on magnetism this month, I thought I would do a little experiment involving the Magnetostrictive Phenomenon. Magnetostriction is a property of a ferromagnetic material whereby it changes shape when it is subjected to a magnetic field. Anyone who has worked with transformers is familiar with the low frequency 50 or 60 Hz hum that can usually be heard coming from the transformer. This is an undesirable magnetostrictive effect that is causing the hum and a subse ...
Karen's Learning Circuit Presentation:   The Learning Circuit 39: Inductor Project: Battery Juicer   got me to playing around with the Battery Juicer Circuit also called the "Joule Thief". You can check out her blog for a schematic and some suggestions. For her build she made a flashlight but I had other ideas for a good use.   When I finally crash at night I put my watch next to the bed. Unfortunately it is quite dark in the room so if I wake up and want to know what time it ...
About 6 months ago we had an Essential Post on Power Distribution:   element14 Essentials - Power IV: Smart Power Distribution   Tonight as I studied a junk circuit board in my bin I came across a good example of the De-Centralized Architecture.   This is a board from an upscale Audio Video Sound System Receiver. The board has multiple micro processors which usually don't have much interest for me but in the lower right corner of the board I saw a parts layout that was repea ...
When a linear power supply is in operation the DC output voltage is regulated. The internal regulator circuit of the power supply takes its source voltage and produces a resistive voltage drop using its power control transistor so that the output voltage is at the desired level.  The difference in voltage potential between the source voltage and the output voltage is a critical quantity as it is one of the two factors in the wasted energy that must be dissipated by the power supply.   ...
Today I watched Karen's makerkaren   Video about building a circuit from a schematic:     https://www.element14.com/community/docs/DOC-91328/l/the-learning-circuit-34-making-a-circuit-from-a-schematic?sr=inbox&ru=360462   At first thought one might wonder what an old dog like me who has been playing with electronics for the last 62 years could learn from a beginners level 11 minute lesson on making a circuit from a schematic. As it turns out there is always a lot t ...
The Process Duration Timer has been a long term project of mine and has gone through several upgrades. Recently I have improved its utility by adding increased flexibility by adding a mechanism for it to disconnect one of its inputs when a process has finished. It has also been modified so that it will track an input voltage that is rising or falling towards a target voltage. An external interface was also designed so that it could track changes in light and temperature. I have covered these upg ...