msiegel Star

Tags  →  electrical eng.

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




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."
"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.
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
when the computer is turned on, a mains outlet gets switched on. simple-minded yet useful :)
yikes, is there some simpler way of making an analog shift register??
i wonder if a cascade of wheatstone bridges could be used to construct a fairly simple but extremely fast analog-to-digital converter...
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




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"
"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 :)
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 :)
includes an example PDF of a CD sized Nipkow disk based on the nbtv.org 32 line standard
or *don't* switch, which sounds like a much better option -- see the page's comments.
overview of several methods of storing/converting energy, and equations for calculating the amounts of energy involved
these brushless motor kits look really neat
interesting arguments for not switching to Pb-free solder
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
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
$100 DIY Scanning Tunneling Microscope? Maybe! I really like the "Disk Scanner" piezo-disc hack this uses, in any case.
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!
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
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
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.