OT - Regulator recommendations (5V & 12V) and how do I create neg ative voltage
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Posts: 46,084
What is a good 5V and 12V regulator? I know they are not terribly expensive
so I guess anything under $10-15 or so would be fine.
Also, I know this is probably a very simple question, but how do I create
negative voltage?
.·°·»
«·°·.
-If everyone throws in their two cents worth, -
-but its a penny for your thoughts...who keeps the profit?-
so I guess anything under $10-15 or so would be fine.
Also, I know this is probably a very simple question, but how do I create
negative voltage?
.·°·»
«·°·.
-If everyone throws in their two cents worth, -
-but its a penny for your thoughts...who keeps the profit?-
Comments
it be a wall transformer or you are building youe own power
supply or what but these are numbers for voltage regulators:
Positive voltage regulators:
78XX
Where XX = voltage regulated
So a 7805 would be a +5vdc regulator,
7812 = +12vdc regulator...etc
(BTW negative voltage regulators are nomenclatured the same way
but start with 79 instead of 78)
(But you need a negative voltage to begin with before regulating it)
Radio shaft carries the 7805 as part# 276-1770 (Rated 1 amp)
In a TO-220 case (The square 3 pin case)
and they have 2 heat sinks part# 276-1363, 276-1368
Jameco and other electronic mags sell the other voltage types
and packages like the TO-3 metal can type.
Jameco charges .29 each while Radio shaft charges $1.49
These components will regulate the voltage but will not filter
the voltage. Again I am not sure of your application.
As for the negative voltage, I ran into a need for this just last
week. I bought come 16x4 LCD's off eBay and after might near pulling
my hair out discovered that the reason I couldn't see anything on the
display was that I needed a negative voltage for the LCD contrast.
I bastardized a MAX232. A 16-pin chip whose purpose is to bring TTL
voltages to RS232 voltage levels. The MAX232 is powered by +5vdc and
along with 4 10uf capacitors, yields a negative voltage on one of the
pins. Its not a lot current, but it worked for me.
There is a chip, part# 7660CPA (Jameco part# 51174) which is easily
available. It is an 8-pin dip IC that is a CMOS +5vdc to -5vdc converter.
Costs $1.09. I need some of these.
Hope this helps,
Bob
At 07:51 AM 5/30/00 -0700, you wrote:
>What is a good 5V and 12V regulator? I know they are not terribly expensive
>so I guess anything under $10-15 or so would be fine.
>
>Also, I know this is probably a very simple question, but how do I create
>negative voltage?
>
>.·°·»
«·°·.
> -If everyone throws in their two cents worth, -
> -but its a penny for your thoughts...who keeps the profit?-
>
>
>
>
>
>
>
good up to 5A .Negative voltages could be easyily created with ICL(or MAX)
7660 or 7662(more current) ICs manufactured by several companies. Good up to
100mA. Need only two external capacitors. Search at findchips.com. Look at
Maxim-ic for regulated outputs and more current and LOW DROPOUT regulators.
(low dropout = more efficiency but more expensive).
ACJacques
Levi Ruiz wrote:
> What is a good 5V and 12V regulator? I know they are not terribly expensive
> so I guess anything under $10-15 or so would be fine.
>
> Also, I know this is probably a very simple question, but how do I create
> negative voltage?
>
> .·°·»
«·°·.
> -If everyone throws in their two cents worth, -
> -but its a penny for your thoughts...who keeps the profit?-
>From: Levi Ruiz <Levi@P...>
>Reply-To: basicstamps@egroups.com
>To: "'basicstamps@egroups.com'" <basicstamps@egroups.com>
>Subject: [noparse][[/noparse]basicstamps] OT - Regulator recommendations (5V & 12V) and how do
>I create neg ative voltage
>Date: Tue, 30 May 2000 07:51:09 -0700
>
>What is a good 5V and 12V regulator? I know they are not terribly expensive
>so I guess anything under $10-15 or so would be fine.
>
>Also, I know this is probably a very simple question, but how do I create
>negative voltage?
>
>.·°·»
«·°·.
> -If everyone throws in their two cents worth, -
> -but its a penny for your thoughts...who keeps the profit?-
>
>
>
>
>
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>LM 317 good adjustable 1.2 to 32V regulator gen.purpose, up to 1.5 A. LM338
>good up to 5A .Negative voltages could be easyily created with ICL(or MAX)
>7660 or 7662(more current) ICs manufactured by several companies. Good
up to
>100mA. Need only two external capacitors. Search at findchips.com.
On a similar note, since this fellow will be powering from an automobile
12V system, and someone has pointed out the surge danger, how best to
protect from these high voltages? I'm building an APRS tracker that will be
powered from 12V and I'd like to protect it from these (potentially 100V+?)...
Best, Duncan
I would use a big zener, like 1 watt, ~20V. They sell transorbs for this
job, but they are simply series back-to-back zeners with an energy (joule)
spec. MOVs are so "soft" that I wouldn't trust them.
Ray McArthur
> On a similar note, since this fellow will be powering from an automobile
> 12V system, and someone has pointed out the surge danger, how best to
> protect from these high voltages? I'm building an APRS tracker that will
be
> powered from 12V and I'd like to protect it from these (potentially
100V+?)...
regards, Jack
orthner@s... wrote:
>
> At 08:40 PM 5/30/00 -0300, AC Jacques wrote:
>
> >LM 317 good adjustable 1.2 to 32V regulator gen.purpose, up to 1.5 A. LM338
> >good up to 5A .Negative voltages could be easyily created with ICL(or MAX)
> >7660 or 7662(more current) ICs manufactured by several companies. Good
> up to
> >100mA. Need only two external capacitors. Search at findchips.com.
>
> On a similar note, since this fellow will be powering from an automobile
> 12V system, and someone has pointed out the surge danger, how best to
> protect from these high voltages? I'm building an APRS tracker that will be
> powered from 12V and I'd like to protect it from these (potentially 100V+?)...
>
> Best, Duncan
tend to fail shorted.
Larry
At 02:30 PM 5/31/00 -0400, you wrote:
>Hi Duncan.
>
>I would use a big zener, like 1 watt, ~20V. They sell transorbs for this
>job, but they are simply series back-to-back zeners with an energy (joule)
>spec. MOVs are so "soft" that I wouldn't trust them.
>
>Ray McArthur
>
>
>> On a similar note, since this fellow will be powering from an automobile
>> 12V system, and someone has pointed out the surge danger, how best to
>> protect from these high voltages? I'm building an APRS tracker that will
>be
>> powered from 12V and I'd like to protect it from these (potentially
>100V+?)...
>
>
>
>
>
>
Larry G. Nelson Sr.
mailto:L.Nelson@i...
http://www.ultranet.com/~nr