Electronics Forum / Electrical Engineering / October 2003

Ive added some more pics on my HV site today.
http://www.jbphonetechleds.fsnet.co.uk/HV_Experiments.htm
Take a look.
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I have another question for the group. Take any transformer, in this case,
I'll use a torus shaped core; one with the primary spiraling around the core
all the way (360 deg.). As I understand, the torus design is efficient and
there is low flux leakage from the core. If this is the ...

Currently I am working on a welding system and I need to use IGBT to
repeatedly cut off the welding current. During the trials, I meet some
big problems and kept burning IGBT's.
The IGBT I am using is CM300HA-12H, the gate driver is M57962L, and a

Hey guys, I am working on my senior design project and I need to incorporate
sensors that will detect dynamic objects like cars, walls, etc... within a
reasonable range from a device (so we were thinking about using sonar
sensor(s) for this)... we also need to somehow track the ...

Here in alaska we purchased American Fittings' (a New Jersey Co.) 1/2 inch
EMT connectors for $68 for 50 each.  The made in China fittings that were of
better quality were $20 for 50 each.   The made in America fittings cannot
be installed with 430 Channelocks without disassembling ...

http://www.itbusiness.ca/index.asp?theaction=61&lid=1&sid=53842
Semiconductor firms step up outsourcing to China
10/23/2003 5:00:00 PM -
Canadian companies follow U.S. trend and move chip tests to Asia

Are you a bright spark Do you want to prove it?
What people have said about The World Quiz League:
"At first glance looks to be a real toughie."
"Any hints forthcoming?"

I am currently building a compressor using a 1.5hp 110/220 volt motor. When
started the pressure builds to about 80psi then cuts out at the thermal
overload (built into the motor). An electrician friend informs me that the
motor overload is more sensitive than the 20 amp breaker, ...

Please could somebody explain how to test for a short circuit using a
digital multi metre, in plain english.
Many thanks in advance
Dave.

How many wires can be on a single pole breaker in a breaker box? also can
you take 3 phase 480 and use each leg to ground  to use 240 volt heaters to
heat water also this equipment is bonded to the same ground wire  I work in
a place that does this and was wondering if it is safe?

I am a novice in the field of electronics, but am curious about the
plans I found in an old book, circa 1960, about building a simple
phase shifter to sidestep the monthly electric bill.
The circuit is simple, 3 Capacitors wired in parallell to a seires of

I understand that the lagging current does not do useful work and reduces
the supply line capacity to supply power. Adding PF correction capacitors of
the right amount balances out the inductive reactance by capacitive
reactance.

Our company intend to build a clean room with possitive pressure in the
room.We will install a blowing fan to suck the air from outside into the
clean room with the damper control.
Can anyone know how to meassure the pressure different between inside and

What exactly is a high impedance fault? I'm trying to figure it out, so I
can get a better picture as to why it doesn't always trigger overcurrent
protective devices and such.
CD

I have a 9VAC GE security system transformer that began to make a faint
buzzing sound and I'm worried this may be unsafe. The noise started a week
ago after several weeks of it *not* buzzing when first installed - or at
least I never noticed it. The unit does *not* appear "hot".