msiegel Star

Tags  →  electrical eng

nikola tesla was here. tesla designed the power system for the electric lighting, and westinghouse built it

one of the websites of tim hunkin, an inspiration to electrical and mechanical engineers, inventors and kinetic artists alike
very interesting... an exceptionally robust battery chemistry that has gone almost unused for 35 years
XD (bored electrical engineers) are the champions

a great introduction to the construction and operation of alternators. thanks to ar0cketman for the find :D
:D this guy is turning a car alternator into a stepper motor! :D maybe a few tinkerers will be inspired to create homemade giant robots

an analysis of several small fm transmitter circuits... this could be handy for a wind/solar powered slow-scan wireless camera :) lifted from technoshaman
it's a ProFile hard drive (remember the Apple Lisa?), turned into a HV power supply :'(

from the page: "Technological troubleshooting, insight and ideas from the experts at Analog Devices to help solve your real-world application challenges."
it looks like it's made of milk chocolate. i must be getting hungry ;)

"Two-channel audio amplifier drives stepper motor"
// a 'class D' audio amp chip as a motor driver. If using a smooth waveform instead of on/off pulses, this is probably a lot more power efficient than normal drivers -- maybe avoiding the need for heatsinks entirely.
using a cheap laminator to fuse the toner to the board -- now there's an interesting spin
lightning and other natural electrical phenomena make low-frequency radio waves we can detect and listen to

the customer review is the best part :D
a classic. conversion and hacking of a payphone. the true hilarity of this video begins at about 25:00, when you realize limor has done the entire conversion for the sole purpose of hacking around the payment mechanism. with continued practice these guys may begin to look like a latter-day secret life of machines :)
different shapes of antennas... helical does work where space is at a premium; although it's not as efficient

this looks like a good technique for soldering magnet wire. i've never seen twisted pair wire that thin before...
a humorous video version of the "bidirectional led" paper. "LED Comm was a project to use ordinary LEDs as both emitters and detectors."

"Employing droop in a voltage regulation circuit increases the headroom for load transients."

// what a clever technique this is
cool! what makes a hard drive go. snagged from ar0cketman

when the computer is turned on, a mains outlet gets switched on. simple-minded yet useful :)
beautiful collection... like going to a museum
yikes, is there some simpler way of making an analog shift register??
cool, but the phone company is not in the energy distribution business... if i were them, i'd track down the leaking energy and "fix" the problem ;-/
a neat and useful project... i like how the author steps through his design process
i wonder if a cascade of wheatstone bridges could be used to construct a fairly simple but extremely fast analog-to-digital converter...
the original solar engine design by Mark Tilden
"The Origin of the Valve"
Exerpts from a talk by inventor of the thermionic valve (aka vacuum tube diode) Dr A J Fleming FRS.
a shift register wired to produce pseudo-random numbers... driving leds so you can see what it's doing :) it's like a stream or a waterfall

"Inspectors Pictorial Reference"

NASA's standard for electrical work

"...provides full color visual examples of acceptance / rejection criteria which may be used for the design, manufacture and inspection of electrical / electronic equipment for high-reliability and space flight applications..."
Denon AKDL1 Dedicated Link Cable
// ouch... but at *that* price, maybe a lambasting is deserved
it seems to be a Theremin... made out of a mug of tea! :) shamelessly lifted from the ever-pink caffeina

simple sensor to help spacecraft maintain normal attitude relative to a light source (e.g., the sun)
A sun sensor for use in orbiting satellites provides accurate attitude control yet eliminates the use of complicated optical components.
Manchester Encoding. Data and clock in one data stream. "what Ethernet uses for its on-wire symbology -- doesn't have any DC component"
excellent idea -- an analog value is converted to a continuous stream of digital pulses, encoded with "pulse density modulation"
"one of the most popular and versatile integrated circuits ever produced"
"Using Pulse Density Modulation to Improve the Efficiency of IGBT Inverters in Induction Heating Applications"

// this abstract outlines a technique i want to use in a class D audio amplifier... with MOSFETs at higher frequency :)
From the page: "hundreds of miles on 80 meters"
using transistors or opamps to buffer a signal, so the signal doesn't distort (due to too much current being drawn from the signal's source)
a very interesting transistor-derived device, used as a pulse generator.
this is one of the better practical references to using common leds as photosensors.
the pdf they're talking about is good, including waveforms that illustrate how the technique works (important for those of us who don't have o-scopes :)
too bad discrete memristors aren't available yet... but this circuit still might help in auto-calibrating a sensor without using a microcontroller :)
really good introduction on where to salvage stepper motors and how to put them to work
includes an example PDF of a CD sized Nipkow disk based on the 32 line standard
a method for transmitting images over an audio-frequency channel
or *don't* switch, which sounds like a much better option -- see the page's comments.
cool, i wonder whether AM or FM is more energy efficient near 1MHz... for a low-voltage solar powered device
a key component of the original, mechanical television technology. the rotating disk acts as an image scanner so a single photodetector can encode the entire scene

i wonder if this has practical applications relating to communications, weather or power-generation
The Great Internet Migratory Box Of Electronics Junk. a very neat idea
wow, heaploads of pinouts all in one place :O
such an ambitious project -- a homemade scanning tunneling electron microscope for around $100
that is a big electrical repair job -- when megawatt underground cables go bad
sounds like the problems with lead-free solder are even worse than having the lead. yet another vote to keep lead-based solders.
a *very* interesting design... i like the virtual ground & capacitance multiplier power supply noise-reduction
great great great great grandmother of the ipod
Fascinating tale of how the 3-prong electrical outlet came to be. Written by billjb!
overview of several methods of storing/converting energy, and equations for calculating the amounts of energy involved
these brushless motor kits look really neat
cool advanced solar power generator design -- i hope it works!
interesting arguments for not switching to Pb-free solder
has a really good section on diodes, and i'm checking out the rest. thanks to ar0cketman! :)
a capacitor is used to store an analogue voltage, and an electronic switch is used to connect the capacitor to an analogue input, refreshing the stored voltage
an in-depth dissection of modern SMPS (for PC power supplies)
guy builds a PWM class D audio amp from vacuum tubes, hahaha! a very cool idea
guy takes apart microwave oven to extract all the interesting components inside
fantastic 1950's product introduction; steve jobs couldn't have done it better

i'm more interested in the mini-review of LTspice, a free and very promising circuit simulator, which runs under Windows or WINE :)
Resonant Converter. A voltage multiplier that eliminates the reactive voltage drop, by adding a resonant inductor. Claims 97% efficiency!
Wire Gauge (AWG) and Current Limits for power transmission. Also calculates voltage drop for a run of wire.
it's not that recent, but it is neat. i like the section on Resonant DC Link Inverters... low on noise and high on efficiency
Nelson Pass designs a JFET power amp in this article, and you can make one too :D
how radio works, & history of its development

$100 DIY Scanning Tunneling Microscope? Maybe! I really like the "Disk Scanner" piezo-disc hack this uses, in any case.
from the page:
"In the 1930s radio pioneer Guglielmo Marconi developed a system of magnetic sound recording using steel tape. This was the same material used to make razor blades, and not surprisingly the fearsome Marconi-Stille recorders were considered so dangerous that technicians had to operate them from another room for safety. Because of the high recording speeds required, they used enormous reels about one metre in diameter, and the thin tape frequently broke, sending jagged lengths of razor steel flying around the studio."
discussion of high-power commercial LED use in DIY optical communications
LIGHT MODULATION VIA ULTRASOUND... maybe this is only of historical interest, but i'd still like to see a home video projector that works off this principle -- relatively cheap & few moving parts :)
technical info on why lead-acid batteries go dead, and how to keep them healthy
what a great audio PSU trick! :D

From the page: "there is a trick to further reduce PSU voltage drop and ripple in stereo LF arrangements. This is achieved by inverting the input signal of one of the channels and reversing the polarity of the load. As a conequence of that, both channels will seldom be drawing current from the same supply rail at the same time and PSU efficiency will be improved."
nice description of how voltage comparators work... includes hot pics!
salvage the fluorescent lamp & inverter from a flatbed scanner
soooo, there are some alkalines actually *designed* to be recharged? hmm...
recharging alkaline batteries... not for the faint of heart, but remember, re-use is even better than recycling!
wow, serious diy electronics & laser experiment
i thought this was going to be Humor, but no. wow.
a transistor can be used in different configurations -- here's what each configuration is good for. this is basic stuff, but really helpful for comprehension!!
Basic DC Power Supply Design
this tutorial makes DC power-supply design seem really easy
...Edison invented the electric company... classic!

info on standard audio connectors, voltages, currents
electronic component definitions for SPICE simulator
TI's stash of ideas for building a variety of electronic devices out of their components
not sure if this produces good-quality noise in the audio frequency range, but it's sure an interesting idea
good article on ac rectification... and a peculiar looking circuit diagram ~:)

6 tiny homemade electrical generators, including a neat piezo experiment
"Low-Cost Audio Delay Line Uses 1-Bit ADC"
neat idea, and very cheap :D
instead of a mechanical switch, MOSFETs are used to turn a conduction path on and off
cool, a diy mini generator / charger / storage battery combo
detailed information about lots of useful integrated circuits
"The Zero Volt Diode" -- a power MOSFET acts like a very low voltage drop diode that switches state at 0V and which is used to conduct negative current from drain to source
wow, just the info i wanted on construction & wiring of stepper and servo motors. how nerdy is that :P
98% efficient Solar Powered Electric Vehicle Motor.

now *that* is an efficient motor
The 3-phase 2-way rectifier / transformer circuit looks really cool. note, this has nothing to do with The Transformers :(
From the page: "an overview with specific pros and cons of the different approaches"
From the page: "What is needed to make a "good" audio Class D amplifier"
From the page: "eliminate cross conduction by forming back-to-back diodes with the body diodes of the MOSFETs".
I wonder if this technique has applications in class b or d audio amplifier design...
Tidy way to construct circuits without etching a PCB.