Question on AMPS

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?

This topic has been discussed in this Usenet group many times before:

The big boys were recently kicking around a similar topic in a related Usenet group:

Don't ASSuME anything. Get a device that is RATED for the task for which you will use it.

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.

Usually, yes.

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.

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.

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.

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.

"ULB"

** 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 !!

** 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.

** 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

"krazy ratbag wanker"

** COMPLETE BOLLOCKS !!!

FOAD you FUCKWIT DAMN TROLL

.... Phil

Once again, Phyllis has seen every specification on the planet.

Back on your meds, freak.

"krazy ratbag wanker"

** COMPLETE BOLLOCKS !!!

FOAD you

FUCKWIT DAMN TROLL !!!!

.... Phil

I said, BACK ON YOUR MEDS, FREAK.

"krazy ratbag wanker"

** COMPLETE BOLLOCKS !!!

FOAD you

FUCKWIT DAMN TROLL !!!!

.... Phil

No it really isn't f****it.

As I said before, GET BACK ON YOUR MEDS, FREAK!

"krazy ratbag wanker"

** COMPLETE BOLLOCKS !!!

FUCK OFF & DIE you

FUCKWIT DAMN TROLL !!!!

.... Phil

Gee, DimWit (DimBulb's half brother), your "send" key is stuck.

BACK ON YOUR MEDS, FREAK.

Fill, Have you ever looked at specs for switched or are you too busy trolling on the internet to look them up.