That would work on my poly88 video card,
with no grayscale.
Dwight
From: cctalk on behalf of Bill Sudbrink
Sent: Monday, April 11, 2016 8:21 AM
To: 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: Voltage regulator with alterna
Chris Elmquist wrote
> On Monday (04/11/2016 at 11:21AM -0400), Bill Sudbrink wrote:
> > Dwight wrote:
> > > How many pixels will the camera have?
> >
> > 1024. The (at the time) secret sauce image sensor
> > is a Mostek MK4008-9. 32x32 pixel image.
>
> Which was a topless DRAM right?
Yes. Dr.
On Monday (04/11/2016 at 11:21AM -0400), Bill Sudbrink wrote:
> Dwight wrote:
> > How many pixels will the camera have?
>
> 1024. The (at the time) secret sauce image sensor
> is a Mostek MK4008-9. 32x32 pixel image.
Which was a topless DRAM right?
Not often a guy gets to use the word "topless
Dwight wrote:
> How many pixels will the camera have?
1024. The (at the time) secret sauce image sensor
is a Mostek MK4008-9. 32x32 pixel image.
Bill S.
The data sheets all spec stability when the output has a fraction of
one uF on the output, but for a variety of (bad) reasons some
designers insist on putting, sometimes, tens thousands of often very
low ESR uF at the output. That's extremely hard on the protection
diode and it'll have to be beefy
Eric,
No, not a series diode (in series with the In or Out), but a diode
connected from Out to In, with the band on the In terminal. It provides a
moderately high current path in the event that the voltage on the Out
exceeds that on the In.
This might occur if the input voltage suddenly drops (sh
On Sun, Apr 10, 2016 at 8:54 PM, drlegendre . wrote:
> I've often wondered why the back-current diode isn't incorporated into the
> die of all common linear regs. Is it that costly, or simply impractical due
> to die space or other considerations?
Because it would introduce additional voltage dro
I've often wondered why the back-current diode isn't incorporated into the
die of all common linear regs. Is it that costly, or simply impractical due
to die space or other considerations?
In fact, I believe that some of the more modern regs do employ it.. just
not the old-standby like LM317, 7805
To protect a regulator against a back volt,
you can put a diode, in reversed polarity.
How many pixels will the camera have?
Dwight
Brent Hilpert wrote:
> Well that's neat.
Thanks.
> I assembled the Cromemco kit version of the Cyclops
> (The kit version presented an interface for a computer
> rather than the scope drive of the magazine article.
I was recently able to acquire the S-100 interface cards
for the Cyclops. I'm ho
Bill, surely you have a pile of 1N400x diodes someplace.
Put 6 in series, forward, between the input and supply.
That should ensure it is safe.
If the voltage is higher than 8 volts, it would mean there
isn't enough current to worry about.
Dwight
On 2016-Apr-08, at 11:58 AM, Bill Sudbrink wrote:
> I don't know why I bothering to be coy about it...
>
> My unit here:
>
> http://wsudbrink.dyndns.org:8080/images/cyclops-latest/P4060005.JPG
> http://wsudbrink.dyndns.org:8080/images/cyclops-latest/P4060006.JPG
>
> Actually, I'm further along
On 2016-Apr-08, at 11:27 AM, Mouse wrote:
>> I archive all data sheets I run across and I found this information
>> on both TI and Fairchild data sheets for the 78H05, LM340 and LM78XX
>> devices - it is usually under a heading called Application Hints and
>> for some reason Fairchild have removed
> > > 1) I have a 12 volt DC supply. 12 volts seems to be
> > >within the VIN range for the 7805s whose data
> > >sheets I've now read. Can I simply apply 12 volts?
> >
> > Yes, but that regulator might get mighty hot! I would
> > not do this for fear of cooking the poor thing.
>
> That
>
> First, a few quick "whys":
>
> 1) The 7805 is actually a Motorola MC7805CP, date
>code 7308 with gold leads. Very hard to exactly
>replace.
Any reason why it would have to be an exact replacement?
In any case, the behaviour of the 7805 if you apply a
voltage to the output with the
I don't know why I bothering to be coy about it...
My unit here:
http://wsudbrink.dyndns.org:8080/images/cyclops-latest/P4060005.JPG
http://wsudbrink.dyndns.org:8080/images/cyclops-latest/P4060006.JPG
Actually, I'm further along than that, but I
don't have more recent photos.
Original unit here
William Donzelli wrote:
> > 1) The 7805 is actually a Motorola MC7805CP, date
> >code 7308 with gold leads. Very hard to exactly
> >replace.
>
> Is that the big flat plastic package with the wide
> flat leads?
Nope, purple ceramic. The heat transfer plate is gold
plated too.
> > 1) I h
Silly question, but then I'm feeling silly today:
Why not just connect the output and input of the 7805 together and power
from the normal +8 line with your +5 supply?
--Chuck
> 1) The 7805 is actually a Motorola MC7805CP, date
>code 7308 with gold leads. Very hard to exactly
>replace.
Is that the big flat plastic package with the wide flat leads? I might
have a few of those around, but I agree, not an easy variant to find.
> 1) I have a 12 volt DC supply. 12
> I archive all data sheets I run across and I found this information
> on both TI and Fairchild data sheets for the 78H05, LM340 and LM78XX
> devices - it is usually under a heading called Application Hints and
> for some reason Fairchild have removed these Hints from the sheets
> you quote.
> In
First, a few quick "whys":
1) The 7805 is actually a Motorola MC7805CP, date
code 7308 with gold leads. Very hard to exactly
replace.
2) As per the design of the unit, the 7805 is soldered
to the foil side of a single sided, copper clad
circuit board with no through hole plating. Li
Keep in mind that "not powered" and "open" are very different things.
What do the data sheets say?
I will admit that this is all careening towards the academic at this point...
--
Will
On Fri, Apr 8, 2016 at 1:31 PM, John Robertson wrote:
> On 04/08/2016 8:54 AM, wulfman wrote:
>>
>> https://ww
On 04/08/2016 8:54 AM, wulfman wrote:
https://www.fairchildsemi.com/datasheets/LM/LM7805.pdf
http://www.ti.com/lit/ds/symlink/lm78l05.pdf ( page 8 gives you the
internals for a low power version )
Nothing in the data sheet saying you cant apply voltage to the output.
As per the low power versi
https://www.fairchildsemi.com/datasheets/LM/LM7805.pdf
http://www.ti.com/lit/ds/symlink/lm78l05.pdf ( page 8 gives you the
internals for a low power version )
Nothing in the data sheet saying you cant apply voltage to the output.
As per the low power version circuit diagram i cant see how you ca
On 04/07/2016 4:41 PM, William Donzelli wrote:
Does this warning assume that there is something on Vin, and not open?
With a quick look at the internal schematic of an old-school 7805, it
seems like what Bill suggests (leaving Vin open) will not actually do
much.
--
Will
This warning is for some
"...if you leave the unregulated rail _unattached_ and put +5
switcher straight onto the regulated +5 rail..."
My error, I read that as "attached".
In any event, just lift both the 7805 IN and OUT pins, and then supply
known-solid +5DC between the OUT and GND pads on the board.
No, you can't fee
Does this warning assume that there is something on Vin, and not open?
With a quick look at the internal schematic of an old-school 7805, it
seems like what Bill suggests (leaving Vin open) will not actually do
much.
--
Will
On Thu, Apr 7, 2016 at 7:23 PM, John Robertson wrote:
> On 04/07/2016 2
On 04/07/2016 2:18 PM, Bill Sudbrink wrote:
drlegendre wrote:
Not saying it's going to smoke-out, but it does
seem like a wonky thing to do.
I disagree about "wonky" let me try with more
diagram and less English:
(+8)
|
VIN|ceramic cap
|-][-
___| |
| 78
On 04/07/2016 2:25 PM, geneb wrote:
On Thu, 7 Apr 2016, Bill Sudbrink wrote:
Maybe I'm overthinking this. If I just put
regulated +5 on the 7805 VIN will it work?
Isn't the minimum input voltage for a 7805, 6vdc?
g.
More like 7VDC input minimum (dropout voltage) for 7805 - there are data
On Thu, 7 Apr 2016, Bill Sudbrink wrote:
Maybe I'm overthinking this. If I just put
regulated +5 on the 7805 VIN will it work?
Isn't the minimum input voltage for a 7805, 6vdc?
g.
--
Proud owner of F-15C 80-0007
http://www.f15sim.com - The only one of its kind.
http://www.diy-cockpits.org/c
Maybe I'm overthinking this. If I just put
regulated +5 on the 7805 VIN will it work?
Bill S.
drlegendre wrote:
> Not saying it's going to smoke-out, but it does
> seem like a wonky thing to do.
I disagree about "wonky" let me try with more
diagram and less English:
(+8)
|
VIN|ceramic cap
|-][-
___| |
| 7805 |--GROUND
|
|
On 04/07/2016 2:03 PM, William Donzelli wrote:
Per his description, the 7805's input will be open. It will not try to
source any current, as it will have none to give.
I suppose there might be a little leakage.
--
Will
If his intention is to bypass the 7805 then it should have both input
and
-Oorspronkelijk bericht-
From: Bill Sudbrink
Sent: Thursday, April 07, 2016 10:38 PM
To: 'General Discussion: On-Topic and Off-Topic Posts'
Subject: Voltage regulator with alternate voltage source...
If you have a circuit which is normally designed to
operate with an unregula
Per his description, the 7805's input will be open. It will not try to
source any current, as it will have none to give.
I suppose there might be a little leakage.
--
Will
On Thu, Apr 7, 2016 at 4:58 PM, drlegendre . wrote:
> Err.. unless the voltage of the switcher is identical to that of the
Err.. unless the voltage of the switcher is identical to that of the 7805,
then one device will source current, and the other will sink it.
Like putting two 6V batteries in parallel, where one is fresh and the other
weak. Current will flow until the potentials are equalized. But with two
regulated
You should be just fine.
On 4/7/2016 1:38 PM, Bill Sudbrink wrote:
> If you have a circuit which is normally designed to
> operate with an unregulated supply, through a regulator...
> say unregulated +8 through a 7805 to a regulated +5 and
> you want to test it independent of the +8 supply, if
> y
If you have a circuit which is normally designed to
operate with an unregulated supply, through a regulator...
say unregulated +8 through a 7805 to a regulated +5 and
you want to test it independent of the +8 supply, if
you leave the unregulated rail unattached and put +5
switcher straight onto the
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