Electronics Forum / Basics / November 2006

I am reading ahead for a microfab class I am taking in January and I've
noticed alot of the literature publishes graphs that characterize a given
phenomenon as a dependency on temperature and thus the x-axis is scaled in
inverse temperature like 1000/K (K^-1).  In some cases the top ...

I repaired a hot water supply unit which is run by 3- phase 440 volts
ac ( no neutral ).
There is a step down to 220 volts tranformer inside the control panal
which also control other switch gear like, temp. controller, contactor.

I need high voltage DC of very small amp. So I used IC 555 to produce
the fluctuating current and step up using a radio transformer to high
AC voltage, to about 2Kv. How do I go about converting this high
voltage AC to high voltage DC?

i have a mobile of LG 2670 and i have forgotten the lock code of the
phone. any one help me for the unlock the phone without any damage.and
i want the unlock code of NOKIA phone also.

Currently the concensus is that J. E. Lilienfeld's transistors of 1926
were never built, and could not have worked.  But every time I read
stuff about Lilienfeld, the hair on the back of my neck stands right
up.   My gut feeling has always been that something is wrong.   I'm led

Part number 74256 2-of-8 addressable latch with reset and enable.
If there somewhere that still has those in stock at reasonable cost?
Or some substitute that would work?

Hi, i recently saw a  LED  flashlight (mag lite) format with an extremely
high intensity light. Does anyone know where i can get one or how to make
one?
Thanks

I have a 1mH, 10A common mode choke. Can I use this as an inductor with
the same specs?
If yes, how? Like (a) connecting one winding and leaving the other open
or (b) paralleling both.

I was toying with an opto-coupler from damaged machinery and
am puzzled by its behaviour. It has the SHARP logo, and was
used as a tachometer with a slotted wheel revolving in a slot
between IR LED and photo-transistor. It has three terminals

I've got two different video toys, one being an archos AV 500 and the
other being a Vantec Avox jukebox.  Both are basically hard drive based
video players.  Both came with AC power bricks that put out around 5v
DC at 2A.

I created an RS422 RJ45 loopback cable by connecting pin 1 to pin 8 and
pin 4 to pin 5.
I also connected a few of the other pins that aren't used since it made
it easier to line everything up into an RJ45 plug.

i have a little problem converting to braille,Braille is a system which
allows a blind person to "read" alphanumerics by feeling a pattern of
six raised dots.For the digits 0-9, only four dots are used, placed
essentially in the four corners of a square, i need to design a ciruit

I have a pic chip and I am trying to control a L293 H-bridge.
Althought I do not get much power out of the Bridge, The motor barely
turns, the 293 is hooked up to the 12v battery. I saw some Hbrodge
circuit already made on the internet ans they gave capacitor and other

I was wondering if anyone could help me with a design of a heat cable
for my new terrarium. I have on fairly expensive cable and would like
to duplicate it. It has a 110v plug at one end and is about 8 feet
long. The end has a small knob which I assume is a resistor of some

Would alternating a lot of capacitors and inductors in series
approximate a Slinky spring?
Bret Cahill