Question on AMPS
ULB
I have a simple question I am sure for you guys, but I am merely an
idiot when it comes to these things and most other things too. :)
Anyway,
I am looking for a momentary key switch (just a lame project) that
can handle at least. 2 AMPS in 12 volt DC. For example, I see
switches that can do 4 amps at 120 volt and that very same switch the
specs state 2 amps at 220 volt. etc. How is that possible? Aren't
amps, amps?
Is it safe to assume if a switch is rated at 4 amps 120 volt AC, it
will still handle or work well with say 12 volt power source in DC?
How exactly does amps work in DC?
Thank you!
ULB
And a follow up. Lets say I have a switch rated at 120 volt AC, 1
AMP. Can I safely push 4 amps at 12 volt DC through it without the
switch failing?
JeffM
>I am looking for a momentary key switch[...]
>that can handle at least. 2 AMPS in 12 volt DC.
>For example, I see switches that can do 4 amps at 120 volt
>and that very same switch the specs state 2 amps at 220 volt. etc.
>How is that possible? Aren't amps, amps?
>
many times before:
http://groups.google.com/group/sci.electronics.basics/search?group=sci.electronics.basics&q=switch+arc&qt_g=Search+this+group
The big boys were recently kicking around a similar topic
in a related Usenet group:
http://groups.google.com/group/sci.electronics.design/browse_frm/thread/c051ee3fd5625431
>Is it safe to assume if a switch is rated at 4 amps 120 volt AC, it
>will still handle or work well with say 12 volt power source in DC?
>
Don't ASSuME anything.
Get a device that is RATED for the task for which you will use it.
whit3rd
> On Dec 30, 10:53 am, ULB <ultralightbackpac...@yahoo.com> wrote:
>
>
>
>
>
> > Hi all,
>
> > I have a simple question I am sure for you guys, but I am merely an
> > idiot when it comes to these things and most other things too. :)
> > Anyway,
>
> > I am looking for a momentary key switch (just a lame project) that
> > can handle at least. 2 AMPS in 12 volt DC. For example, I see
> > switches that can do 4 amps at 120 volt and that very same switch the
> > specs state 2 amps at 220 volt. etc. How is that possible? Aren't
> > amps, amps?
If it were only the current-carrying capacity, yes. Unfortunately,
you have to consider the dynamics of opening a closed
switch and closing an open one. DC can strike an arc
and keep it burning until your wire evaporates, while AC
will extinguish an arc on the next zero-crossing (no more
than 8 milliseconds from strike).
Closing an open switch, there's significant bounce, which
(depending on the connected circuitry) can cause small sparking/
arcing that erodes the electrical contacts.
> > Is it safe to assume if a switch is rated at 4 amps 120 volt AC, it
> > will still handle or work well with say 12 volt power source in DC?
Usually, yes.
> And a follow up. Lets say I have a switch rated at 120 volt AC, 1
> AMP. Can I safely push 4 amps at 12 volt DC through it without the
> switch failing?
When the switch is closed, it doesn't matter WHAT the other
circuitry has for voltage; the switch has zero volts. No, it
isn't likely to pass 4A if it's rated at 1A.
krw
<ultralight...@yahoo.com> wrote:
>Hi all,
>
>I have a simple question I am sure for you guys, but I am merely an
>idiot when it comes to these things and most other things too. :)
>Anyway,
>
>I am looking for a momentary key switch (just a lame project) that
>can handle at least. 2 AMPS in 12 volt DC. For example, I see
>switches that can do 4 amps at 120 volt and that very same switch the
>specs state 2 amps at 220 volt. etc. How is that possible? Aren't
>amps, amps?
No. Think of a switch as a valve. If the pressure is too high it'll
burst. A switch will not be useful at all at a certain voltage.
Now stop thinking of it as a valve. ;-) A switch also has to break
the arc cause by the contacts separating. The larger the voltage the
longer the arc. The higher the current the stronger/heavier the arc.
Also note that 120VAC has a peak voltage of ~170V.
>Is it safe to assume if a switch is rated at 4 amps 120 volt AC, it
>will still handle or work well with say 12 volt power source in DC?
Absolutely *not*. AC arcs tend to self extinguish as the voltage
drops to zero. DC doesn't have this advantage. It's common to see a
switch rated at perhaps 10A@120VAC and only 1A@12VDC.
>How exactly does amps work in DC?
The heat/work caused/done by 120VAC (RMS for the pickers of nits) and
120VDC is the same. How it gets there and how it has to be treated is
very much different.
Phil Allison
"ULB"
>
> I am looking for a momentary key switch (just a lame project) that
> can handle at least. 2 AMPS in 12 volt DC. For example, I see
> switches that can do 4 amps at 120 volt and that very same switch the
> specs state 2 amps at 220 volt. etc. How is that possible? Aren't
> amps, amps?
** As other have indicated - it is the ability of a switch to SWITCH a
circuit on AND off that brings about its amp rating.
That amp rating will change DRAMATICALLY with the various things folk want
switches to SWITCH !!
> Is it safe to assume if a switch is rated at 4 amps 120 volt AC, it
> will still handle or work well with say 12 volt power source in DC?
** In limited circumstances - yes.
The restricting conditions are that the LOAD being switched is NOT highly
inductive or capacitive nor one that produces large surge currents.
> How exactly does amps work in DC?
** Switch ratings are highly dependant of the NATURE of the load being
switched.
But YOU decided that such a trivial detail did not matter.
Like most PITA usenet trolls, you posted a waaaay too broad question that
was irrelevant to your need for specific information.
Care get real ???
.... Phil
Phil Allison
"krazy ratbag wanker"
> It's common to see a
> switch rated at perhaps 10A@120VAC and only 1A@12VDC.
** COMPLETE BOLLOCKS !!!
FOAD you FUCKWIT DAMN TROLL
.... Phil
krw
wrote:
Once again, Phyllis has seen every specification on the planet.
Back on your meds, freak.
Phil Allison
"krazy ratbag wanker"
> It's common to see a
> switch rated at perhaps 10A@120VAC and only 1A@12VDC.
** COMPLETE BOLLOCKS !!!
FOAD you
FUCKWIT DAMN TROLL !!!!
.... Phil
krw
wrote:
>
I said, BACK ON YOUR MEDS, FREAK.
Phil Allison
"krazy ratbag wanker"
> It's common to see a
> switch rated at perhaps 10A@120VAC and only 1A@12VDC.
** COMPLETE BOLLOCKS !!!
FOAD you
FUCKWIT DAMN TROLL !!!!
.... Phil
krw
wrote:
>
>"krazy ratbag wanker"
>
>> It's common to see a
>> switch rated at perhaps 10A@120VAC and only 1A@12VDC.
>
>
>** COMPLETE BOLLOCKS !!!
No it really isn't fuckwit.
> FOAD you
>
> FUCKWIT DAMN TROLL !!!!
>
As I said before, GET BACK ON YOUR MEDS, FREAK!
Phil Allison
"krazy ratbag wanker"
> It's common to see a
> switch rated at perhaps 10A@120VAC and only 1A@12VDC.
** COMPLETE BOLLOCKS !!!
FUCK OFF & DIE you
FUCKWIT DAMN TROLL !!!!
.... Phil
krw
wrote:
>
>
>"krazy ratbag wanker"
>
>> It's common to see a
>> switch rated at perhaps 10A@120VAC and only 1A@12VDC.
>
>
>** COMPLETE BOLLOCKS !!!
Gee, DimWit (DimBulb's half brother), your "send" key is stuck.
> FUCK OFF & DIE you
>
> FUCKWIT DAMN TROLL !!!!
BACK ON YOUR MEDS, FREAK.
sparky
Fill, Have you ever looked at specs for switched or are you too busy
trolling on the internet to look them up.
Phil Allison
"sparky"
> Have you ever looked at specs for switches ...
** How about YOU go look ?
Be an absolute first - I bet.
Fucking idiot.
... Phil
sparky
Hi Phil,
Since you do not know how to look up information I am posting it for
you. I randomly picked a switch from the Digikey catalog which turned
out to be a Honeywell 1TL1 series switch. The resistive rating for
this switch is 125 VAC 15 amps . The resistive rating at 155 VDC is .
75 amps.
Glad I could help you on your quest for knowledge.
Tom Biasi
"sparky" <spar...@yahoo.com> wrote in message
news:26be2144-11e0-4fe9...@34g2000yqp.googlegroups.com...
Hi Phil,
Sparky,
Take a look at the Honeywell data sheet here:
http://sccatalog.honeywell.com/printfriendly.asp?FAM=tr&PN=1TL1-2
Regards,
Tom
sparky
> "sparky" <sparky...@yahoo.com> wrote in message
This is a more in depth data sheet.
http://sccatalog.honeywell.com/pdbdownload/images/1tl1.series.chart.1.pdf
.
Phil Allison
"sparky"
"Phil Allison"
> "sparky"
>
> > Have you ever looked at specs for switches ...
>
> ** How about YOU go look ?
>
> Be an absolute first - I bet.
>
> Fucking idiot.
Since you do not know how to look up information I am posting it for
you.
** Piss off - you tenth wit troll.
I randomly picked a switch from the Digikey catalog which turned
out to be a Honeywell 1TL1 series switch. The resistive rating for
this switch is 125 VAC 15 amps . The resistive rating at 155 VDC is .
75 amps.
** The resistive load specs are very typical and amount to:
15 amps at 120VAC & 20 amps at 12VDC.
Piss off - you tenth wit troll.
.... Phil