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Quotation of the day

M

MassiveProng

Jan 1, 1970
0
perhaps you should have read the two links.

I did, dumbfuck. You didn't.

BOTH have "to make certain" in then. One, as the first given
definition, and the other, a bit farther down.

Try again, gloss over boy.
 
M

MassiveProng

Jan 1, 1970
0
Once again, the mighty ass has opened his mouth to roar, but merely
drooled down his chest, instead.


At least it hits his chest. Yours runs down your leg.

Stop talking out of your ass, boy.

Bwuahahahahaha!
 
H

Homer J Simpson

Jan 1, 1970
0
Ok - how do we send 100,000 volts to Homer's PC? :)

Not by telegraph - they don't do that any more.

How can we put internet controlled electric dog collars around Jim's and
John's necks?
 
J

John Larkin

Jan 1, 1970
0
Nope. You haven't been paying attention so who is retarded? I actually have
two separate trade qualifications, some advanced trade qualifications, a
degree and considerable experience in a number of strange technical or
related fields.

Then why do you never make technical contributions to the group?

What are these trade qualifications and degree?

John
 
T

Terry Given

Jan 1, 1970
0
Jim said:
Jim Thompson wrote:
[snip]
So ask a technically useful question already ;-)

...Jim Thompson

OK,

Im playing with an el-cheapo smps controller. Its peak-current-mode
control, and uses the BE junction of an NPN to detect peak current, and
turn the switch off. Of course Vbe varies strongly with T.

Normally I use a TL431 etc for voltage feedback; it has a nice stable
reference. I just choose my current sense resistor for min Vbe (max T),
and the magic of -ve feedback makes sure all is well. yay.

the circuit is pretty simple, the 431 pulls down on a pnp (crappy
mirror) which feeds current into an R, also connected to the base (there
is an R from B to Rs) so the base voltage is the sum of IRs and the
error amp output voltage.


This time, however, I want to use it as a current regulator. There is
still a setpoint, but no error amp (other than the NPN), so alas all my
-ve feedback "magic" stops working, so I have to:

a) temp-comp the setpoint (or NPN, but I want to keep I*Rs low), or

b) add some other form of current sensor, a T-stable reference and an
error amp, which I dont want to do.


so far the best I have come up with is placing a Vbe multiplier (using
the other transistor in the NPN's sot-323 package) in series with my
setpoint voltage. If I choose the Vbe multiplier scale factor to be the
reciprocal of the resistive divider formed from Vsetpoint to Rs, then
the divided-down scaled-up Vbe temperature change exactly (ish) cancels
out the dVbe of the NPN.

kinda:


Vsetpoint----[Vbe multiplier]---[R1]----+-----B of CE NPN
| \
0V--[Rs]--+---------------------[R2]----+ 0V
|
to switch Source (or E)


R1,R2 >> Rs

so I get:

Vbe1 - dVbe1 = (I*Rs)*R1/(R1+R2) + (Vs - K*(Vbe2 - dVbe2))*R2/(R1+R2)

and if the 2 BJTs are at the same temperature, then dVbe1 = dVbe2

so all I have to do is choose K = (R1+R2)/R1.


but it feels kinda icky.

Cheers
Terry


Can you post a schematic? I don't understand words very well ;-)

...Jim Thompson

Not really, I dont have access to ABSE. But I did send you an email.

Thanks,
Terry
 
H

Homer J Simpson

Jan 1, 1970
0
Then why do you never make technical contributions to the group?

Says who? You're the one who likes to start pissing contests.
What are these trade qualifications and degree?

Like I'd tell you.
 
J

Jim Thompson

Jan 1, 1970
0
Jim said:
Jim Thompson wrote:
[snip]

So ask a technically useful question already ;-)

...Jim Thompson

OK,

Im playing with an el-cheapo smps controller. Its peak-current-mode
control, and uses the BE junction of an NPN to detect peak current, and
turn the switch off. Of course Vbe varies strongly with T.

Normally I use a TL431 etc for voltage feedback; it has a nice stable
reference. I just choose my current sense resistor for min Vbe (max T),
and the magic of -ve feedback makes sure all is well. yay.

the circuit is pretty simple, the 431 pulls down on a pnp (crappy
mirror) which feeds current into an R, also connected to the base (there
is an R from B to Rs) so the base voltage is the sum of IRs and the
error amp output voltage.


This time, however, I want to use it as a current regulator. There is
still a setpoint, but no error amp (other than the NPN), so alas all my
-ve feedback "magic" stops working, so I have to:

a) temp-comp the setpoint (or NPN, but I want to keep I*Rs low), or

b) add some other form of current sensor, a T-stable reference and an
error amp, which I dont want to do.


so far the best I have come up with is placing a Vbe multiplier (using
the other transistor in the NPN's sot-323 package) in series with my
setpoint voltage. If I choose the Vbe multiplier scale factor to be the
reciprocal of the resistive divider formed from Vsetpoint to Rs, then
the divided-down scaled-up Vbe temperature change exactly (ish) cancels
out the dVbe of the NPN.

kinda:


Vsetpoint----[Vbe multiplier]---[R1]----+-----B of CE NPN
| \
0V--[Rs]--+---------------------[R2]----+ 0V
|
to switch Source (or E)


R1,R2 >> Rs

so I get:

Vbe1 - dVbe1 = (I*Rs)*R1/(R1+R2) + (Vs - K*(Vbe2 - dVbe2))*R2/(R1+R2)

and if the 2 BJTs are at the same temperature, then dVbe1 = dVbe2

so all I have to do is choose K = (R1+R2)/R1.


but it feels kinda icky.

Cheers
Terry


Can you post a schematic? I don't understand words very well ;-)

...Jim Thompson

Not really, I dont have access to ABSE. But I did send you an email.

Thanks,
Terry

Thanks, got it! Will observe in the morning.

...Jim Thompson
 
M

Michael A. Terrell

Jan 1, 1970
0
MassiveProng said:
At least it hits his chest. Yours runs down your leg.

Stop talking out of your ass, boy.

Bwuahahahahaha!


You have both of those fields all to yourself, as usual.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
T

Terry Given

Jan 1, 1970
0
Homer said:
Says who? You're the one who likes to start pissing contests.




Like I'd tell you.

why not? its not like its top secret or anything. I have:

- BTech(hons) [for USians, this aint a 2-year associate degree. Its
since become a BE]
- most of an ME (some USians offered me stacks of cash to emigrate so I
never finished writing my thesis, but was a straight A+ student. I
actually sat my Advanced Control Systems paper at Boston University
(cant recall exact name of uni, but I got there on the Green Line)
instead of AK Uni)
- ESTA (toaster repair trade qual)
- ESTB (3-phase fixed wiring toaster repair trade qual)
- a plague of various technical courses on EMI, lightning protection
blah blah free lunch

the ESTx were done solely so I am legally able to mess with
electrickery, instead of having to pay for a sparky. And I learned a
good trick, which is to make the earth wire in a plug 1-2cm longer than
all the rest, so its the last one to come out when yanking on the cord.


Cheers
Terry
 
H

Homer J Simpson

Jan 1, 1970
0
the ESTx were done solely so I am legally able to mess with electrickery,
instead of having to pay for a sparky.

I'm a sparky in two countries and plan to add a third.
And I learned a good trick, which is to make the earth wire in a plug
1-2cm longer than all the rest, so its the last one to come out when
yanking on the cord.

If you've anchored the cord right it won't come out.

The best trick is to remember our motto: "One flash and you're ash!"
 
E

Eeyore

Jan 1, 1970
0
Absolutely not.


Yes there damn well is !

I did, dumbfuck. You didn't.

Yes he did !

There's a reason that insurance policies aren't called ensurance policies. One
is simply a financial matter, the other would need the company to be a God.


BOTH have "to make certain" in then.

Oh right. So that makes them identical in meaning does it ?

One, as the first given definition, and the other, a bit farther down.

Try again, gloss over boy.

So how much do you pay for your car ensurance ?

I don't suppose you understand the difference between alternate and alternative
either ?

Graham
 
E

Eeyore

Jan 1, 1970
0
Homer said:
I'm a sparky in two countries and plan to add a third.


If you've anchored the cord right it won't come out.

Ever ?

Graham
 
T

Terry Given

Jan 1, 1970
0
Homer said:
I'm a sparky in two countries and plan to add a third.

I toyed with the idea of becoming a sparky, but I have to do 2,000 hours
of cable jerking. Im pretty sure I wont get my hourly rate for that....

oddly enough, comms cable counts. weird huh?

The tutors at tech suggested I just stick with the ESTB. The only things
I cant do are:

- install fixed wiring

(and who really wants to do that)

- work in back of switchboard

(and for what I do, thats not really necessary either)

If you've anchored the cord right it won't come out.

in theory. practice usually differs.
The best trick is to remember our motto: "One flash and you're ash!"

I'm very careful. 20mF charged to 900Vdc is something to be wary of.

Go on Homie, spill re. your degree. it wont kill you....

Cheers
Terry
 
M

MassiveProng

Jan 1, 1970
0
Absolutely not.



Yes there damn well is !



Yes he did !

There's a reason that insurance policies aren't called ensurance policies. One
is simply a financial matter, the other would need the company to be a God.




Oh right. So that makes them identical in meaning does it ?



So how much do you pay for your car ensurance ?

I don't suppose you understand the difference between alternate and alternative
either ?

Graham


The ALTERNATIVE to you understanding this issue is for me to ignore
you for your utter stupidity.

One does not get ensured. Yeah, dumbfuck, I know that.

BUT, one can say "Ensure that you handle this problem."

AS WELL AS "Insure that you handle this problem."

As well as: "Assure that you handle this problem."

In THAT context, either is correct, as well as the third.

You fucktards are THICK in the skull, and thin on the brain tissue!

If you had any brains, it would be YOU that would understand that
there are ALTERNATE meanings for whichever one you seem to think is
incorrect.

Second definition for insure:

2 : to make certain especially by taking necessary measures and
precautions.

First definition for Ensure:

: to make sure, certain, or safe : guarantee

NOW, READ CLOSELY, DISPHIT:

SYNONYMS for ENSURE:

synonyms ensure, insure, assure, secure mean to make a thing or person
sure. ensure, insure, and assure are interchangeable in many contexts
where they indicate the making certain or inevitable of an outcome,

Now grow the **** up, and shut the **** up about it.
 
E

Eeyore

Jan 1, 1970
0
MassiveProng said:
The ALTERNATIVE to you understanding this issue is for me to ignore
you for your utter stupidity.

One does not get ensured. Yeah, dumbfuck, I know that.

Thank you for agreeing that ensure and insure DO NOT mean the same thing !

Graham
 
E

Eeyore

Jan 1, 1970
0
MassiveProng said:
The ALTERNATIVE to you understanding this issue is for me to ignore
you for your utter stupidity.

One does not get ensured. Yeah, dumbfuck, I know that.

You *DO* ? So why did you say insure and ensure mean the same ?

BUT, one can say "Ensure that you handle this problem."
Correct.


AS WELL AS "Insure that you handle this problem."

No. Well you could take out an insurance policy in case of the problem I guess.

As well as: "Assure that you handle this problem."

That means yet something else still.

In THAT context, either is correct, as well as the third.

And they all mean different things. Unfortunately sloppy US use of English has
confused you.

Graham
 
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