Are the 3 and 7 volt outputs both positive?
What's a linear regurgitator?
)CMOS 555 and output transistor Frank?
So, since there is no possible rational justification for reelecting the
The lost art of wire wrap. You can buy boards in Eurocard or (perhaps
Gasp!. What's this?, a programmed micro to drive a switcher?.
as president. Re-electing him would have no justification. Otherwise,
I'd say: Don't let the mosfets scare you... Then you have plenty of good
Chris,Joerg wrote:
Yes, same in medical. After all, doctors are not engineers and are
Ah well that's a help. Most of the people who use inverters *think* they are
engineers and they are the worst type of all for blowing things up.
usually under a lot of stress. So we anticipate all the abuse that we
ever heard of from the Service and QC folks and then redesign in
safeguards.
Which adds to the cost
Re the fuse....
No, it can blow and it should. But it needs to indicate that it did so
and spares must be available. Ideally versions you can by at the local
auto parts store.
You missed the point. In order for this hypothetical inverter to operate to
it's full spec, it's battery fuse must be able to pass 1000 amps for 10
seconds. Now what diode do you propose to use that will blow that fuse and
*never*, not even for 1 pS allow the voltage across it to exceed the voltage
drop of the body diodes in the inverter?
How big would this "idiot"diode" (as we call them) be? Similar size to the
inverter? Bigger?
It could also be a "sacrificial diode". As long as it can be purchased
as a spare at reasonable cost.
Refer to the above and show me one at reasonable cost that will pass 1000 amps
with less voltage drop than the mosfet body diodes for long enough to blow the
fuse.
Now that will add to the product cost
since the contact areas need to be rather huge.
The Prosine is protected against AC backfeed, but it's expensive, so people
buy
the cheap ones which are not protected! Then complain when it blows up when
they backfeed it.
Why is that so expensive? Can't it be a fast sense circuit which rapidly
opens the H-bridge?
Which is indeed what it is in the ProSine. In actual fact protection against
backfeed is almost inherent in this type of inverter and doesn't require *that*
much extra.
But in this case there is very large inductance between the IGBTs and the
output port which thereby slows the voltage rise time as seen by the IGBTs when
it is backfed.
That isn't the case in a modified sinewave inverter so no matter *how* fast you
make the sense circuit, the overcurrent on the IGBTs is instant. They blow at
the same time as the overcurrent circuit senses the problem.
The only way this can work is to increase the output impedance of the voltage
up converter, which thereby reduces the efficiency.
All these suggestions to protect the units are things we looked at 20 years
ago. There is *nothing* that hasn't been suggested, analysed, tried and then
finally rejected!
It took a while but meantime most RF transmitters
are pretty well protected against a sudden loss of antenna connection,
Again you have inductance to help.
It would be somehwhat more difficult to protect the transmitter output against
someone connecting it to another transmitter output with 100 times the power
capability, the same output voltage and an output impedance of about 1 ohm.
Which is a fair analogy to an AC backfeed.
Now think how much more dificult it would be if the original transmitter was
operating in class D.
Or buy an expensive inverter in the first place which has less chance of
failing!
Well, even the most sophisticated equipment can fail. If failure can
cause great harm or losses then I'd always want a spare. Just as I don't
go over a mountain pass, or pretty much anywhere, without a spare tire.
Murphy says that even the best inverter could fail and that if it ever
does it will be on a Saturday afternoon.
Indeed. Which is why have 2 on my boat!
I'd normally agree with that statement. But in the case of inverters, as you
yourself seem to agree, people buy the cheapest (including yourself).
Guilty.
Consequently it has become accepted that inverters blow up all the time.
Only
the cheap ones do that.
I never had one blow up.
But you're not likely to connect it to the batteries the wrong way round, or
backfeed it, or connect a heart interface remote panel to a prosine. Or plug a
temperature sensor into the remote panel, or fill it with salt water etc etc
etc
These are things that get done.
Try a *variable speed* electric drill on it. Don't come asking me to help when
it blows up
I see the point. But the cost delta between high end and low end does
not have to be more than 10dB ;-)
It will remain so as long as customers in general buy the cheap ones. When they
finally realise that the expensive ones *are* better the prices will fall even
faster than they already are doing.
I personally would prefer 20dB difference
Gibbo
Or 4 times louder ?I personally would prefer 20dB difference
Chris,
dont forget money = power, so 20dB = 100x more expensive.....
Ok, what about:
The airframe is an inanimate object, its lifetime is rated in hours of
Boy! You sure do read a lot- huh dumbass? And look at all those numbers-Fred Bloggs <nospam@nospam.com> wrote in message news:<4173CE95.2010308@nospam.com>...
Tom Seim wrote:
Fred Bloggs <nospam@nospam.com> wrote in message news:<4173A0D9.2060704@nospam.com>...
John Larkin wrote:
On Mon, 18 Oct 2004 01:33:54 +0100, Paul Burridge
pb@notthisbit.osiris1.co.uk> wrote:
On Sun, 17 Oct 2004 19:18:20 GMT, "Clarence" <no@No.com> wrote:
I liked the P38.
Saw a lot of them at the training base.
Flew half a mile to one side of my house when landing.
The P38 was a double-action Walther 9mm semi-automatic pistol commonly
issued to German troops during WW2. They don't fly - unless you throw
them.
P38 Lightning, the Fork-Tailed Devil. It wasn't that useful over
Europe, but it wreaked hell against the Japanese. It was a flight of
seventeen P38's that ambushed Yamamoto near Bougainville on April 15,
1943.
John
The p38 was much like you- A PIECE OF SHIT!- the Jap zeroes tore them up
big time- no competition. Then the Grumman HELLCAT came along and
turned that picture around -big time- end of story for the Jap Zeroes.
You are amazingly misinformed for a veteran. The label "Fork-Tailed
Devil" was the Japanese term. The superior altitude, speed, armament
and armor of the P38 rendered the Zero defenseless
(http://p-38online.com/):
"On my first confrontation with the P-38, I was astonished to find an
American aircraft that could outrun, outclimb, and outdive our Zero
which we thought was the most superior fighter plane in the world. The
Lightning's great speed, its sensational high altitude performance,
and especially its ability to dive and climb much faster than the Zero
presented insuperable problems for our fliers. The P-38 pilots, flying
at great height, chose when and where they wanted to fight with
disastrous results for our own men. The P-38 boded ill for the future
and destroyed the morale of the Zero fighter Pilot."...Saburo Sakai,
Japanese Ace
Note that your quote is from a Japanese "ace"- well they all became
extinct after the HELLCAT came on board
You're still batting ZERO! The Japanese had 8,000 planes and pilots
held in reserve to defend against the inevitable invasion.
Fortunately, the A-bombs precluded that (the plutonium for "Fat Man" -
the Nagasaki bomb - was produced here).
That's not what Kerry said- he said he made significant contributions to
That statement is a real good illustration of the depth of your
The mast will ring at some frequency. For a short time there will be a
something other than "having a Gaussian amplitude distribution", go ahead.