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John Wiltrout's Blog

155 posts
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 ...
jw0752

One Less Inconvenience

Posted by jw0752 Top Member Dec 9, 2018
I just finished a build that took me about 30 hours. While I am working on things I always try to be mindful of the flow of the work and whether there are things that are inconvenient in the shop environment. This could be related to the placement or organization of parts as well as tools. Inconvenience and trouble can mean there is an opportunity to improve. It is easy to accept things the way they are presently and soldier on but this leaves one with a situation that will frustrate over and ov ...
The computer in my lab is very important to me. This of course is very subjective as its contents and utilities are understood and utilized only be me and so someday, when I can no longer use it, it will go directly from my lab to the computer recycle facility. In the meantime I do everything in my power to keep it clean, backed up, and with a protected UPS power supply. The original battery of the 650 Watt UPS is long since failed and when it did I bought a car battery and rewired things so tha ...
I like to build simple bench test and experimentation equipment, particularly power supplies. Those of you who have been here for a while have had to endure numerous power supply builds from me. My previous builds have been fairly traditional with a mains to operational voltage step down transformer, rectification and filtering, and then a linear voltage and current controller circuit to the outputs. Over the years I have experimented with different variations on this theme. A couple times ago w ...
As I worked today at the Retro Electronics Store where I help out two days a week I came across a box of metal cylinders with four pins on one end. They looked like this:     They were called car radio vibrators and they came from another age. I immediately remembered my first car, a fairly beat up 1957 Chevrolet and its radio. Cruising around was great fun but it was even better with the radio blaring out the tunes of the day. The radios that were being used at that time had not ye ...
A week or so ago I wrote about my experience with a pair of Aven  10826F Flush Cutters   https://www.element14.com/community/groups/test-and-measurement/blog/2018/11/06/my-kingdom-for-a-good-pair-of-flush-cutters   I was very pleased with the response and the way the discussion carried over into the quality of small specialty pliers as well.   In the previous post dougw  mentioned having some good quality pliers capable of picking up 40 Ga wire. He asked how many pli ...
My latest experiments revolve around using the Chinese linear power supply board that has been the heart of many of my bench supply builds but rather than powering it with the tradition transformer and bridge arrangement I want to power it with a switch mode power supply.   Here is a schematic of the linear power supply board as supplied from the vendor:     My enthusiasm often gets ahead of my eyes and my brain so in typical form I assembled a board and left off the bridge di ...
I have been bugging a new friend, Neil, whom I was introduced to by genebren but whom I had never met face to face to let me know when his company would be attending an electronics show somewhere near my home. Neil is the founder and inspiration behind the company Tag-Connect out of San Fancisco. Neil has started a revolution in board connectors that simplify and economize on space and board cost without sacrificing connection integrity. Neil is also the person who is using his company and influ ...
I have had a Dual 601 turntable for many years, perhaps 50, and it used to work great. Sometime ago it started acting strange as the motor became unstable and would power up and lock on a higher RPM than proper. From the information on the internet it seemed that this was a design problem and would not be easily solved. I tried to fix it anyway. I tried external electronics to see if I could make it come up to the proper speed. I even messed with the pole spacing on the stater but the internet h ...
This is a second build of of a Simple DC Electronic Load project using information that I learned about curing Oscillations in a separate discussion: https://www.element14.com/community/thread/64985?start=15&tstart=0 The knowledge that I received from other element 14 members as well as things that I learned from the bad decisions that I made on the first build made me want to give it another try. Here is the blog from the first build: https://www.element14.com/community/people/jw0752/bl ...