Driver to drive?

Jim Thompson · Jun 8, 2012

On Fri, 08 Jun 2012 15:30:03 -0500, flipper <flipper@fish.net> wrote:

On Fri, 08 Jun 2012 09:31:33 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Thu, 07 Jun 2012 23:38:42 -0500, flipper <flipper@fish.net> wrote:

Frankly, Jim, I think you've become so attuned to trading barbs with
'whoever' that the 'chip', so to speak, is on your shoulder and you
misinterpreted his lack of knowledge as 'smart mouthed'.

He said from day one he knows next to nothing so when you toss out
what are to you 'blindingly obvious' things like "bias current" he
doesn't know what you mean because, as he explained, 'to him' bias is
a voltage. That not being "smart mouthed," it's just all he knows from
what he's managed to 'pick up' from somewhere.

I suspect you're used to 'challenging' EEs to 'think' but that isn't
going to work here because he isn't an EE and will likely not
understand what you're asking. You need to 'explain' things to him,
not ask him to 'explain' it to you expecting that, in doing so, the
'light bulb' will go off and he'll 'realize' where you're going and
the thing he's overlooked.

So, what should I do, just design it for him?

Might actually be easier.

But you're correct, maybe I nudged Dave like I would an engineer, but
isn't this mild...

It is for someone who knows what you mean, but not for someone who
knows close to nothing. After all, the very first response was
confusion about "bias current." Well, if he doesn't know what it is
then he can't calculate it, right? And it's not because he can't
divide V by R. He didn't understand the jargon "bias current" and we
might as well ask him to calculate the fubar ratio. What's a fubar?

Worse, actually, because he was at least somewhat familiar with "bias
voltage" so instead of a completely alien term it seemed inconsistent
with the limited knowledge he did have..

[JT]

"Back up and do a little math. Calculate the bias current in that
last stage. (In fact, calculate all your stage biases.)

How much voltage gain do you need?

What is the load impedance? Is it a speaker?"

[Dave]

"Don't mean to be critical, but these seem like very generic"
questions."

==

What the hell does that mean?

I think it may have meant something akin to "how do those (generic)
things relate to my (specific) noisy speaker?"

Nothing like, "How...", or an answer to my gain question.

I certainly don't want to get into an 'argument' over this but you're
being rather 'selective' in the quotes. For "bias current" he tried to
'guess' you meant collector current (in the last stage) and answered
180 mA. As for gain, he figured he had enough. That, of course, isn't
what you asked but what difference does it make? (I imagine him
wondering since he probably didn't see that being related to his
stated 'problem'). He answered the speaker and load question: "Load is
an 8 Ohm speaker."

And after what you view as a mystery question he queried "What,
specifically, are you thinking?"

Now, I can see that, to you, the phrase "what are you thinking?" might
have sounded like a 'challenge' but I think he simply had no idea
where you were going, what the purpose of the 'calculations' were
(plus he didn't know what "bias current" meant), what the point was,
and how it related to his, not necessarily correct, concept of the
problem, which may not be the issues you were addressing.

Its not an uncommon problem when 'expert' speaks to 'novice' because
what is so engrained that it's instinctively 'knee jerk' obvious to
one, including the jargon, is 'huh?' to the other.

...Jim Thompson

Maybe it'd be easier if I simply design it for them. No controversy,
and maybe I gain a customer when they can't understand it O

Tom Del Rosso · Jun 9, 2012

Jim Thompson wrote:

"Don't mean to be critical, but these seem like very generic"
questions."

What the hell does that mean?

I think it may have meant something akin to "how do those (generic)
things relate to my (specific) noisy speaker?"

That showed a complete lack of common sense analytical ability. It isn't
just a lack of knowledge. He was being closed-minded.

I actually remember the first time I heard of bias current. It was upon
reading the datasheet for the LM319 comparator about 25 years ago. It took
about 100 ms to realize that, where there is a voltage applied to a finite
resistance, there is also a current, and it comes from the same source. The
reason Dave didn't realize that is not because it was too hard for him.
It's because he didn't know who you were, and assumed you didn't know what
you were talking about, so he didn't even think about it.

He might not know how to calculate Thevinin equivalents (that the parallel
resistance formula is applied to series resistors is not obvious) but he
didn't ask how. He just assumed you were wrong. Yes, he said it nicely at
first, but it was still an arrogant assumption.

--

Reply in group, but if emailing add one more
zero, and remove the last word.

josephkk · Jun 9, 2012

On Fri, 08 Jun 2012 15:30:03 -0500, flipper <flipper@fish.net> wrote:

On Fri, 08 Jun 2012 09:31:33 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Thu, 07 Jun 2012 23:38:42 -0500, flipper <flipper@fish.net> wrote:

Frankly, Jim, I think you've become so attuned to trading barbs with
'whoever' that the 'chip', so to speak, is on your shoulder and you
misinterpreted his lack of knowledge as 'smart mouthed'.

He said from day one he knows next to nothing so when you toss out
what are to you 'blindingly obvious' things like "bias current" he
doesn't know what you mean because, as he explained, 'to him' bias is
a voltage. That not being "smart mouthed," it's just all he knows from
what he's managed to 'pick up' from somewhere.

I suspect you're used to 'challenging' EEs to 'think' but that isn't
going to work here because he isn't an EE and will likely not
understand what you're asking. You need to 'explain' things to him,
not ask him to 'explain' it to you expecting that, in doing so, the
'light bulb' will go off and he'll 'realize' where you're going and
the thing he's overlooked.

So, what should I do, just design it for him?

Might actually be easier.

But you're correct, maybe I nudged Dave like I would an engineer, but
isn't this mild...

It is for someone who knows what you mean, but not for someone who
knows close to nothing. After all, the very first response was
confusion about "bias current." Well, if he doesn't know what it is
then he can't calculate it, right? And it's not because he can't
divide V by R. He didn't understand the jargon "bias current" and we
might as well ask him to calculate the fubar ratio. What's a fubar?

Worse, actually, because he was at least somewhat familiar with "bias
voltage" so instead of a completely alien term it seemed inconsistent
with the limited knowledge he did have..

[JT]

"Back up and do a little math. Calculate the bias current in that
last stage. (In fact, calculate all your stage biases.)

How much voltage gain do you need?

What is the load impedance? Is it a speaker?"

[Dave]

"Don't mean to be critical, but these seem like very generic"
questions."

=
What the hell does that mean?

I think it may have meant something akin to "how do those (generic)
things relate to my (specific) noisy speaker?"

Nothing like, "How...", or an answer to my gain question.

I certainly don't want to get into an 'argument' over this but you're
being rather 'selective' in the quotes. For "bias current" he tried to
'guess' you meant collector current (in the last stage) and answered
180 mA. As for gain, he figured he had enough. That, of course, isn't
what you asked but what difference does it make? (I imagine him
wondering since he probably didn't see that being related to his
stated 'problem'). He answered the speaker and load question: "Load is
an 8 Ohm speaker."

And after what you view as a mystery question he queried "What,
specifically, are you thinking?"

Now, I can see that, to you, the phrase "what are you thinking?" might
have sounded like a 'challenge' but I think he simply had no idea
where you were going, what the purpose of the 'calculations' were
(plus he didn't know what "bias current" meant), what the point was,
and how it related to his, not necessarily correct, concept of the
problem, which may not be the issues you were addressing.

Its not an uncommon problem when 'expert' speaks to 'novice' because
what is so engrained that it's instinctively 'knee jerk' obvious to
one, including the jargon, is 'huh?' to the other.

...Jim Thompson

BTW flipper this group is supposedly for working engineers. Persons like
Dave should stay in s.e.b instead.

?-)

flipper · Jun 9, 2012

On Fri, 08 Jun 2012 13:59:06 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Fri, 08 Jun 2012 15:30:03 -0500, flipper <flipper@fish.net> wrote:

On Fri, 08 Jun 2012 09:31:33 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Thu, 07 Jun 2012 23:38:42 -0500, flipper <flipper@fish.net> wrote:

Frankly, Jim, I think you've become so attuned to trading barbs with
'whoever' that the 'chip', so to speak, is on your shoulder and you
misinterpreted his lack of knowledge as 'smart mouthed'.

He said from day one he knows next to nothing so when you toss out
what are to you 'blindingly obvious' things like "bias current" he
doesn't know what you mean because, as he explained, 'to him' bias is
a voltage. That not being "smart mouthed," it's just all he knows from
what he's managed to 'pick up' from somewhere.

I suspect you're used to 'challenging' EEs to 'think' but that isn't
going to work here because he isn't an EE and will likely not
understand what you're asking. You need to 'explain' things to him,
not ask him to 'explain' it to you expecting that, in doing so, the
'light bulb' will go off and he'll 'realize' where you're going and
the thing he's overlooked.

So, what should I do, just design it for him?

Might actually be easier.

But you're correct, maybe I nudged Dave like I would an engineer, but
isn't this mild...

It is for someone who knows what you mean, but not for someone who
knows close to nothing. After all, the very first response was
confusion about "bias current." Well, if he doesn't know what it is
then he can't calculate it, right? And it's not because he can't
divide V by R. He didn't understand the jargon "bias current" and we
might as well ask him to calculate the fubar ratio. What's a fubar?

Worse, actually, because he was at least somewhat familiar with "bias
voltage" so instead of a completely alien term it seemed inconsistent
with the limited knowledge he did have..

[JT]

"Back up and do a little math. Calculate the bias current in that
last stage. (In fact, calculate all your stage biases.)

How much voltage gain do you need?

What is the load impedance? Is it a speaker?"

[Dave]

"Don't mean to be critical, but these seem like very generic"
questions."

==

What the hell does that mean?

I think it may have meant something akin to "how do those (generic)
things relate to my (specific) noisy speaker?"

Nothing like, "How...", or an answer to my gain question.

I certainly don't want to get into an 'argument' over this but you're
being rather 'selective' in the quotes. For "bias current" he tried to
'guess' you meant collector current (in the last stage) and answered
180 mA. As for gain, he figured he had enough. That, of course, isn't
what you asked but what difference does it make? (I imagine him
wondering since he probably didn't see that being related to his
stated 'problem'). He answered the speaker and load question: "Load is
an 8 Ohm speaker."

And after what you view as a mystery question he queried "What,
specifically, are you thinking?"

Now, I can see that, to you, the phrase "what are you thinking?" might
have sounded like a 'challenge' but I think he simply had no idea
where you were going, what the purpose of the 'calculations' were
(plus he didn't know what "bias current" meant), what the point was,
and how it related to his, not necessarily correct, concept of the
problem, which may not be the issues you were addressing.

Its not an uncommon problem when 'expert' speaks to 'novice' because
what is so engrained that it's instinctively 'knee jerk' obvious to
one, including the jargon, is 'huh?' to the other.

...Jim Thompson

Maybe it'd be easier if I simply design it for them. No controversy,
and maybe I gain a customer when they can't understand it O

LOL. There ya go: lemonade from lemons.

...Jim Thompson

flipper · Jun 9, 2012

On Fri, 08 Jun 2012 22:03:13 -0700, josephkk
<joseph_barrett@sbcglobal.net> wrote:

BTW flipper this group is supposedly for working engineers.

Oh? That's the first I heard of it.

Persons like
Dave should stay in s.e.b instead.

Probably a good place to ask questions.

But let's give the boy some credit. He did post a schematic, which is
more on topic than a lot of what goes on around here.

?-)

Ian Field · Jun 9, 2012

"flipper" <flipper@fish.net> wrote in message
news:6jq5t7t60tto1r4ad68pjpt0t04unehus7@4ax.com...

On Fri, 08 Jun 2012 22:03:13 -0700, josephkk
joseph_barrett@sbcglobal.net> wrote:

BTW flipper this group is supposedly for working engineers.

Oh? That's the first I heard of it.

Persons like
Dave should stay in s.e.b instead.

Probably a good place to ask questions.

But let's give the boy some credit. He did post a schematic, which is
more on topic than a lot of what goes on around here.

And the person ripping on him was the worst offender.

Jim Thompson · Jun 9, 2012

On Fri, 08 Jun 2012 22:03:13 -0700, josephkk
<joseph_barrett@sbcglobal.net> wrote:

On Fri, 08 Jun 2012 15:30:03 -0500, flipper <flipper@fish.net> wrote:

On Fri, 08 Jun 2012 09:31:33 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Thu, 07 Jun 2012 23:38:42 -0500, flipper <flipper@fish.net> wrote:

Frankly, Jim, I think you've become so attuned to trading barbs with
'whoever' that the 'chip', so to speak, is on your shoulder and you
misinterpreted his lack of knowledge as 'smart mouthed'.

He said from day one he knows next to nothing so when you toss out
what are to you 'blindingly obvious' things like "bias current" he
doesn't know what you mean because, as he explained, 'to him' bias is
a voltage. That not being "smart mouthed," it's just all he knows from
what he's managed to 'pick up' from somewhere.

I suspect you're used to 'challenging' EEs to 'think' but that isn't
going to work here because he isn't an EE and will likely not
understand what you're asking. You need to 'explain' things to him,
not ask him to 'explain' it to you expecting that, in doing so, the
'light bulb' will go off and he'll 'realize' where you're going and
the thing he's overlooked.

So, what should I do, just design it for him?

Might actually be easier.

But you're correct, maybe I nudged Dave like I would an engineer, but
isn't this mild...

It is for someone who knows what you mean, but not for someone who
knows close to nothing. After all, the very first response was
confusion about "bias current." Well, if he doesn't know what it is
then he can't calculate it, right? And it's not because he can't
divide V by R. He didn't understand the jargon "bias current" and we
might as well ask him to calculate the fubar ratio. What's a fubar?

Worse, actually, because he was at least somewhat familiar with "bias
voltage" so instead of a completely alien term it seemed inconsistent
with the limited knowledge he did have..

[JT]

"Back up and do a little math. Calculate the bias current in that
last stage. (In fact, calculate all your stage biases.)

How much voltage gain do you need?

What is the load impedance? Is it a speaker?"

[Dave]

"Don't mean to be critical, but these seem like very generic"
questions."

==

What the hell does that mean?

I think it may have meant something akin to "how do those (generic)
things relate to my (specific) noisy speaker?"

Nothing like, "How...", or an answer to my gain question.

I certainly don't want to get into an 'argument' over this but you're
being rather 'selective' in the quotes. For "bias current" he tried to
'guess' you meant collector current (in the last stage) and answered
180 mA. As for gain, he figured he had enough. That, of course, isn't
what you asked but what difference does it make? (I imagine him
wondering since he probably didn't see that being related to his
stated 'problem'). He answered the speaker and load question: "Load is
an 8 Ohm speaker."

And after what you view as a mystery question he queried "What,
specifically, are you thinking?"

Now, I can see that, to you, the phrase "what are you thinking?" might
have sounded like a 'challenge' but I think he simply had no idea
where you were going, what the purpose of the 'calculations' were
(plus he didn't know what "bias current" meant), what the point was,
and how it related to his, not necessarily correct, concept of the
problem, which may not be the issues you were addressing.

Its not an uncommon problem when 'expert' speaks to 'novice' because
what is so engrained that it's instinctively 'knee jerk' obvious to
one, including the jargon, is 'huh?' to the other.

...Jim Thompson

BTW flipper this group is supposedly for working engineers. Persons like
Dave should stay in s.e.b instead.

?-)

See...

From: Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com>
Newsgroups: alt.binaries.schematics.electronic
Subject: Re: Okay, so, what am I missing here?
Date: Fri, 08 Jun 2012 09:48:31 -0700
Message-ID: <u5b4t7hm2n9j4lcnh4vn6omn4c35jj3001@4ax.com>

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice

Jim Thompson · Jun 9, 2012

On Sat, 09 Jun 2012 01:07:23 -0500, flipper <flipper@fish.net> wrote:

On Fri, 08 Jun 2012 13:59:06 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Fri, 08 Jun 2012 15:30:03 -0500, flipper <flipper@fish.net> wrote:

On Fri, 08 Jun 2012 09:31:33 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Thu, 07 Jun 2012 23:38:42 -0500, flipper <flipper@fish.net> wrote:

Frankly, Jim, I think you've become so attuned to trading barbs with
'whoever' that the 'chip', so to speak, is on your shoulder and you
misinterpreted his lack of knowledge as 'smart mouthed'.

He said from day one he knows next to nothing so when you toss out
what are to you 'blindingly obvious' things like "bias current" he
doesn't know what you mean because, as he explained, 'to him' bias is
a voltage. That not being "smart mouthed," it's just all he knows from
what he's managed to 'pick up' from somewhere.

I suspect you're used to 'challenging' EEs to 'think' but that isn't
going to work here because he isn't an EE and will likely not
understand what you're asking. You need to 'explain' things to him,
not ask him to 'explain' it to you expecting that, in doing so, the
'light bulb' will go off and he'll 'realize' where you're going and
the thing he's overlooked.

So, what should I do, just design it for him?

Might actually be easier.

But you're correct, maybe I nudged Dave like I would an engineer, but
isn't this mild...

It is for someone who knows what you mean, but not for someone who
knows close to nothing. After all, the very first response was
confusion about "bias current." Well, if he doesn't know what it is
then he can't calculate it, right? And it's not because he can't
divide V by R. He didn't understand the jargon "bias current" and we
might as well ask him to calculate the fubar ratio. What's a fubar?

Worse, actually, because he was at least somewhat familiar with "bias
voltage" so instead of a completely alien term it seemed inconsistent
with the limited knowledge he did have..

[JT]

"Back up and do a little math. Calculate the bias current in that
last stage. (In fact, calculate all your stage biases.)

How much voltage gain do you need?

What is the load impedance? Is it a speaker?"

[Dave]

"Don't mean to be critical, but these seem like very generic"
questions."

==

What the hell does that mean?

I think it may have meant something akin to "how do those (generic)
things relate to my (specific) noisy speaker?"

Nothing like, "How...", or an answer to my gain question.

I certainly don't want to get into an 'argument' over this but you're
being rather 'selective' in the quotes. For "bias current" he tried to
'guess' you meant collector current (in the last stage) and answered
180 mA. As for gain, he figured he had enough. That, of course, isn't
what you asked but what difference does it make? (I imagine him
wondering since he probably didn't see that being related to his
stated 'problem'). He answered the speaker and load question: "Load is
an 8 Ohm speaker."

And after what you view as a mystery question he queried "What,
specifically, are you thinking?"

Now, I can see that, to you, the phrase "what are you thinking?" might
have sounded like a 'challenge' but I think he simply had no idea
where you were going, what the purpose of the 'calculations' were
(plus he didn't know what "bias current" meant), what the point was,
and how it related to his, not necessarily correct, concept of the
problem, which may not be the issues you were addressing.

Its not an uncommon problem when 'expert' speaks to 'novice' because
what is so engrained that it's instinctively 'knee jerk' obvious to
one, including the jargon, is 'huh?' to the other.

...Jim Thompson

Maybe it'd be easier if I simply design it for them. No controversy,
and maybe I gain a customer when they can't understand it O

LOL. There ya go: lemonade from lemons.

...Jim Thompson

Lemonade (with Gain = 250X)...

Newsgroups: alt.binaries.schematics.electronic
Subject: Re: Okay, so, what am I missing here? -
Intercom_Possibility_KISS.png
Date: Sat, 09 Jun 2012 14:48:07 -0700
Message-ID: <03h7t7dcnppbqfa7sm2ekfll87gav6gnmr@4ax.com>

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice

josephkk · Jun 12, 2012

On Sat, 09 Jun 2012 11:30:45 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Fri, 08 Jun 2012 22:03:13 -0700, josephkk
joseph_barrett@sbcglobal.net> wrote:

On Fri, 08 Jun 2012 15:30:03 -0500, flipper <flipper@fish.net> wrote:

snip
Now, I can see that, to you, the phrase "what are you thinking?" might
have sounded like a 'challenge' but I think he simply had no idea
where you were going, what the purpose of the 'calculations' were
(plus he didn't know what "bias current" meant), what the point was,
and how it related to his, not necessarily correct, concept of the
problem, which may not be the issues you were addressing.

Its not an uncommon problem when 'expert' speaks to 'novice' because
what is so engrained that it's instinctively 'knee jerk' obvious to
one, including the jargon, is 'huh?' to the other.

...Jim Thompson

BTW flipper this group is supposedly for working engineers. Persons like
Dave should stay in s.e.b instead.

?-)

See...

From: Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com
Newsgroups: alt.binaries.schematics.electronic
Subject: Re: Okay, so, what am I missing here?
Date: Fri, 08 Jun 2012 09:48:31 -0700
Message-ID: <u5b4t7hm2n9j4lcnh4vn6omn4c35jj3001@4ax.com

...Jim Thompson

Slick. I'll remember that one for education of others.

?-)

Mark Zenier · Jun 12, 2012

In article <44m5t79dbbljh51a1g0milkecnutpbj06o@4ax.com>,
josephkk <joseph_barrett@sbcglobal.net> wrote:

BTW flipper this group is supposedly for working engineers.

No, it isn't.

Mark Zenier mzenier@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)

Jethro_uk · Jun 13, 2012

On Wed, 13 Jun 2012 07:20:54 +0100, Andy Burns wrote:

Jethro_uk wrote:

Can anyone suggest an electronic circuit which can take 2 400W loads,
and switch instantaneously between them, so that to a connected
monitor, the draw appears consistent (i.e. no spikes or troughs) ?

what sort of loads (AC or DC, inductive such as motors or resistive such
as incandescent lamps or heaters)? are the two loads the same type of
load?

Sorry, should have said for UK AC Mains. Let's say both loads are like a
half bar fire - so plain resistive loads. I'm picturing a black box which
plugs into the wall, and which has 2 sockets. When the load on one socket
is removed, the box switches power to the other socket.

X-posted to sci.electronics.design as previous poster suggested.

John Williamson · Jun 13, 2012

NT wrote:

On Jun 13, 9:28 am, Jethro_uk <jethro...@hotmailbin.com> wrote:
On Wed, 13 Jun 2012 07:20:54 +0100, Andy Burns wrote:
Jethro_uk wrote:
Can anyone suggest an electronic circuit which can take 2 400W loads,
and switch instantaneously between them, so that to a connected
monitor, the draw appears consistent (i.e. no spikes or troughs) ?
what sort of loads (AC or DC, inductive such as motors or resistive such
as incandescent lamps or heaters)? are the two loads the same type of
load?
Sorry, should have said for UK AC Mains. Let's say both loads are like a
half bar fire - so plain resistive loads. I'm picturing a black box which
plugs into the wall, and which has 2 sockets. When the load on one socket
is removed, the box switches power to the other socket.

X-posted to sci.electronics.design as previous poster suggested.

that's simple, just 2 triacs controlled by whatever is making the
decision. Triacs would need to be switched at zero crossing to avoid
any glitch.

The details of the switching vary depending on whether the load is
resistive or inductive.

And how fussy the monitor is about consumption spikes. Even with

something like a cooker hob element or light bulb, there'll be a short
term increase in consumption as it gets up to temperature, and if it's
something like a capacitor start motor, the surge as it gets up to speed
will be noticeable, to say the least.

Automatically switching from one outlet to another when one load is
removed is not too hard to arrange, again depending on how fussy you are
about cases where the load is unplugged at, say, peak voltage, and
whether you're talking about millisecond current peaks and gaps or not.

--
Tciao for Now!

John.

Rod Speed · Jun 13, 2012

Jethro_uk <jethro_uk@hotmailbin.com> wrote

Andy Burns wrote
Jethro_uk wrote

Can anyone suggest an electronic circuit which can take 2 400W loads,
and switch instantaneously between them, so that to a connected
monitor, the draw appears consistent (i.e. no spikes or troughs) ?

what sort of loads (AC or DC, inductive such as motors or resistive such
as incandescent lamps or heaters)? are the two loads the same type of
load?

Sorry, should have said for UK AC Mains. Let's say both loads are like a
half bar fire - so plain resistive loads. I'm picturing a black box which
plugs into the wall, and which has 2 sockets. When the load on one
socket is removed, the box switches power to the other socket.

Why the requirement that 'switch instantaneously between them, so that to
a connected monitor, the draw appears consistent (i.e. no spikes or
troughs)'

Thatâs the hard thing to do.

Rod Speed · Jun 13, 2012

NT <meow2222@care2.com> wrote

Jethro_uk <jethro...@hotmailbin.com> wrote
Andy Burns wrote
Jethro_uk wrote

Can anyone suggest an electronic circuit which can take 2 400W loads,
and switch instantaneously between them, so that to a connected
monitor, the draw appears consistent (i.e. no spikes or troughs) ?

what sort of loads (AC or DC, inductive such as motors or resistive such
as
incandescent lamps or heaters)? are the two loads the same type of load?

Sorry, should have said for UK AC Mains. Let's say both loads are like
a half bar fire - so plain resistive loads. I'm picturing a black box
which
plugs into the wall, and which has 2 sockets. When the load on one
socket is removed, the box switches power to the other socket.

that's simple,

We'll see...

just 2 triacs controlled by whatever is making the decision.
Triacs would need to be switched at zero crossing to avoid
any glitch.

But 'whatever is making the decision' gets tricky doing the
detection that the first load is gone at the zero crossing point
in time. By definition if the first load goes away at other than
the zero crossing time, you will see some spike or trough.

The details of the switching vary depending on whether the load is
resistive or inductive.

He said its resistive.

Rod Speed · Jun 13, 2012

NT <meow2222@care2.com> wrote

Rod Speed <rod.speed....@gmail.com> wrote
NT <meow2...@care2.com> wrote
Jethro_uk <jethro...@hotmailbin.com> wrote
Andy Burns wrote
Jethro_uk wrote

Can anyone suggest an electronic circuit which can take 2 400W loads,
and switch instantaneously between them, so that to a connected
monitor, the draw appears consistent (i.e. no spikes or troughs) ?

what sort of loads (AC or DC, inductive such as motors or resistive
such as
incandescent lamps or heaters)? are the two loads the same type of
load?

Sorry, should have said for UK AC Mains. Let's say both loads are like
a half bar fire - so plain resistive loads. I'm picturing a black box
which
plugs into the wall, and which has 2 sockets. When the load on one
socket is removed, the box switches power to the other socket.

that's simple,

We'll see...

just 2 triacs controlled by whatever is making the decision.
Triacs would need to be switched at zero crossing to avoid
any glitch.

But 'whatever is making the decision' gets tricky doing the
detection that the first load is gone at the zero crossing point
in time. By definition if the first load goes away at other than
the zero crossing time, you will see some spike or trough.

Yes. One could switch it fast with a triac, and if necessary even
use a big LC or switched mode circuit to smooth the transition.

I'd rather use mosfets so there is less to smooth out.

Still gets tricky detecting the removal of the first load
quickly enough to avoid any switching glitch unless he
is happy with some system where the user effectively
has a 'switch loads' button and lets the system switch
when it wants to at say the next zero crossing etc.

That would be completely trivial to do.

The details of the switching vary depending
on whether the load is resistive or inductive.

He said its resistive.

Yes. Is it safe to assume its totally resistive?

Doesn't really matter if he's happy with a 'switch loads'
button that produces a switch at zero current flowing.

Tho there would still be a problem as John pointed
out with the other load being cold initially etc.

And why does someone need to hide load
switching from an upstream monitor?

Yeah, I asked him that, but he hasn't been back yet.

NT · Jun 13, 2012

On Jun 13, 9:28 am, Jethro_uk <jethro...@hotmailbin.com> wrote:

On Wed, 13 Jun 2012 07:20:54 +0100, Andy Burns wrote:
Jethro_uk wrote:

Can anyone suggest an electronic circuit which can take 2 400W loads,
and switch instantaneously between them, so that to a connected
monitor, the draw appears consistent (i.e. no spikes or troughs) ?

what sort of loads (AC or DC, inductive such as motors or resistive such
as incandescent lamps or heaters)? are the two loads the same type of
load?

Sorry, should have said for UK AC Mains. Let's say both loads are like a
half bar fire - so plain resistive loads. I'm picturing a black box which
plugs into the wall, and which has 2 sockets. When the load on one socket
is removed, the box switches power to the other socket.

X-posted to sci.electronics.design as previous poster suggested.

that's simple, just 2 triacs controlled by whatever is making the
decision. Triacs would need to be switched at zero crossing to avoid
any glitch.

The details of the switching vary depending on whether the load is
resistive or inductive.

NT

Jethro_uk · Jun 13, 2012

On Wed, 13 Jun 2012 19:39:21 +1000, Rod Speed wrote:

Jethro_uk <jethro_uk@hotmailbin.com> wrote
Andy Burns wrote
Jethro_uk wrote

Can anyone suggest an electronic circuit which can take 2 400W loads,
and switch instantaneously between them, so that to a connected
monitor, the draw appears consistent (i.e. no spikes or troughs) ?

what sort of loads (AC or DC, inductive such as motors or resistive
such as incandescent lamps or heaters)? are the two loads the same
type of load?

Sorry, should have said for UK AC Mains. Let's say both loads are like
a half bar fire - so plain resistive loads. I'm picturing a black box
which plugs into the wall, and which has 2 sockets. When the load on
one socket is removed, the box switches power to the other socket.

Why the requirement that 'switch instantaneously between them, so that
to a connected monitor, the draw appears consistent (i.e. no spikes or
troughs)'

Thatâs the hard thing to do.

I was just curious ... in the ongoing smart meter debates (e.g. http://
forums.theregister.co.uk/forum/1/2012/05/24/british_gas_alertme/) it
seems some people claim that smart meters will tell energy companies who
is growing cannabis, by looking for energy draws consistent with growlamps
coming on/off at set times. It seemed to be that a simple way to negate
that would be something which gave the *appearance* of a permanently-on
appliance drawing 400W. OK, it would add to the cost of such an
operation, but it would hide the profile from the meter.

I suspect there's space there for some snake-oil devices ....

Rod Speed · Jun 13, 2012

Jethro_uk <jethro_uk@hotmailbin.com> wrote

Rod Speed wrote
Jethro_uk <jethro_uk@hotmailbin.com> wrote
Andy Burns wrote
Jethro_uk wrote

Can anyone suggest an electronic circuit which can take 2 400W loads,
and switch instantaneously between them, so that to a connected
monitor, the draw appears consistent (i.e. no spikes or troughs) ?

what sort of loads (AC or DC, inductive such as motors or resistive
such as incandescent lamps or heaters)? are the two loads the same
type of load?

Sorry, should have said for UK AC Mains. Let's say both loads are like
a half bar fire - so plain resistive loads. I'm picturing a black box
which plugs into the wall, and which has 2 sockets. When the load on
one socket is removed, the box switches power to the other socket.

Why the requirement that 'switch instantaneously between them, so that
to a connected monitor, the draw appears consistent (i.e. no spikes or
troughs)'

Thatâs the hard thing to do.

I was just curious ... in the ongoing smart meter debates
(e.g.
http://forums.theregister.co.uk/forum/1/2012/05/24/british_gas_alertme/)
it seems some people claim that smart meters will tell energy companies
who
is growing cannabis, by looking for energy draws consistent with growlamps
coming on/off at set times.

Most of ours appear to just bypass the meter completely so they get free
power.

Least thatâs what it appears from the fact that those caught
usually get charged with bypassing the meter too.

It seemed to be that a simple way to negate that
would be something which gave the *appearance*
of a permanently-on appliance drawing 400W.

Dunno, my superficial reaction is that that would
likely be very obvious, that it isnt turned off when
most are sleeping etc.

Not sure what they normally do lights wise tho, whether
they normally run them 24/7 for that sort of crop.

OK, it would add to the cost of such an operation,

Not enough to matter if they are paying for the power used.

but it would hide the profile from the meter.

Dunno, see above.

I suspect there's space there for some snake-oil devices ....

It certainly wouldnât be hard to do a system that switched
loads with a timer and switched them at the zero crossing
with a triac. That would be good enough for the meter to
not notice anything much, even tho you would get a
measurable spike in the current with the inrush current
to the previous off grow lamps.

Maybe not tho if they deliberately check for spikes like that.
The switch on surge wouldnât be trivial with that sort of load.

You could avoid that by not switching the 'off' loads
completely off tho. Then you wouldnât get any spike
on switching at all. Very easy to do in fact.

If its not an academic question and you actually are
growing them yourself, I'd do it with an X10 system
with a dimmer for each load and switch it with a PC.

Not that much harder to do without a PC.

Donât know what you'd do about having a load that
is on 24/7 if thatâs whats done with grow lamps tho.
Or a load thatâs the same in summer and winter, there
cant be too many normal domestic situations like that.

Guess you could just grow different numbers of plants
in summer and winter and hope they donât wonder
about why there is no time in spring and autumn with
no real heating or cooling demand.

Guess you could just not grow much in spring and autumn,
but it would likely be tricky to have that in synch with
unseasonable weather when everyone else is heating or
cooling and they can see that from their other meter readings.

It'd be a lot simpler to just power the grow lights before
the meter. You are flouting the law already, so you might
as well flout that law too. It isnt likely to make much
difference penalty wise if you get caught.

NT · Jun 13, 2012

On Jun 13, 9:57 am, John Williamson <johnwilliam...@btinternet.com>
wrote:

NT wrote:
On Jun 13, 9:28 am, Jethro_uk <jethro...@hotmailbin.com> wrote:
On Wed, 13 Jun 2012 07:20:54 +0100, Andy Burns wrote:
Jethro_uk wrote:
Can anyone suggest an electronic circuit which can take 2 400W loads,
and switch instantaneously between them, so that to a connected
monitor, the draw appears consistent (i.e. no spikes or troughs) ?
what sort of loads (AC or DC, inductive such as motors or resistive such
as incandescent lamps or heaters)? are the two loads the same type of
load?
Sorry, should have said for UK AC Mains. Let's say both loads are like a
half bar fire - so plain resistive loads. I'm picturing a black box which
plugs into the wall, and which has 2 sockets. When the load on one socket
is removed, the box switches power to the other socket.

X-posted to sci.electronics.design as previous poster suggested.

that's simple, just 2 triacs controlled by whatever is making the
decision. Triacs would need to be switched at zero crossing to avoid
any glitch.

The details of the switching vary depending on whether the load is
resistive or inductive.

And how fussy the monitor is about consumption spikes. Even with
something like a cooker hob element or light bulb, there'll be a short
term increase in consumption as it gets up to temperature, and if it's
something like a capacitor start motor, the surge as it gets up to speed
will be noticeable, to say the least.

Automatically switching from one outlet to another when one load is
removed is not too hard to arrange, again depending on how fussy you are
about cases where the load is unplugged at, say, peak voltage, and
whether you're talking about millisecond current peaks and gaps or not.

If the monitoring device isnt very fussy, a simple relay would do the
whole job. If youre using say 1kW plug-in heaters, rewind the relay
coil to operate on 4A, and the contacts will switch to load 2 when
load 1 no longer draws current. To move back topowering load 1, unplug
load 2 and press a button that momentarily connects power to load 1.
The relay then latches. Note that the relay should switch the live,
and its coil be in the neutral line, otherwise the pushbutton would
short the coil.

NT

NT · Jun 13, 2012

On Jun 13, 10:44 am, "Rod Speed" <rod.speed....@gmail.com> wrote:

NT <meow2...@care2.com> wrote

Jethro_uk <jethro...@hotmailbin.com> wrote
Andy Burns wrote
Jethro_uk wrote
Can anyone suggest an electronic circuit which can take 2 400W loads,
and switch instantaneously between them, so that to a connected
monitor, the draw appears consistent (i.e. no spikes or troughs) ?
what sort of loads (AC or DC, inductive such as motors or resistive such
as
incandescent lamps or heaters)? are the two loads the same type of load?
Sorry, should have said for UK AC Mains. Let's say both loads are like
a half bar fire - so plain resistive loads. I'm picturing a black box
which
plugs into the wall, and which has 2 sockets. When the load on one
socket is removed, the box switches power to the other socket.
that's simple,

We'll see...

just 2 triacs controlled by whatever is making the decision.
Triacs would need to be switched at zero crossing to avoid
any glitch.

But 'whatever is making the decision' gets tricky doing the
detection that the first load is gone at the zero crossing point
in time. By definition if the first load goes away at other than
the zero crossing time, you will see some spike or trough.

Yes. One could switch it fast with a triac, and if necessary even use
a big LC or switched mode circuit to smooth the transition.

The details of the switching vary depending on whether the load is
resistive or inductive.

He said its resistive.

Yes. Is it safe to assume its totally resistive?

And why does someone need to hide load switching from an upstream
monitor?

NT

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