Question about push button on/off switch specs.

[sp838]

Hello, I am interested in purchasing some of your LED on/off push button switches, but I have a technical question I'm hoping you can answer before I make my purchase. This is the switch I am interested in:

http://www.adafruit.com/products/559#Technical_Details

How much amperage can this switch handle at 14VDC? I see that the switch is rated to 3A at 250VDC, so at lower voltage, can it handle higher amperage? Can it handle 10A at 14VDC? What is the highest amperage it can handle at 14VDC? I would like to replace the keyed ignition switches on my motorcycles, which are on a 10 A circuit, in a system which varies from 12 to 14VDC depending on the rpm of the bike...

Thank you very much,

-Simon

[adafruit_support_mike]

A switch's current and voltage ratings don't really translate to a power rating.

The voltage rating tells you how well isolated the conductors are. You can apply 250v without fear of arcing across the gap between the contacts or breakdown of the insulation.

The current rating tells you (very roughly) how much metal is in the connection path. The total resistance is listed at less than 50 milliohms, so it doesn't matter whether you have 1v or 100v, 1A of current will produce less than 50mV across the switch. That translates to about 50mW of heat, and the heat is the important thing. Most conductors are rated for the amount of current that will raise them to a steady 35 degrees C in a 25C environment.

Taking 50mohm as an upper limit, sending 3A through the switch would produce a voltage drop of 150mV. That translates to 450mW of heat, so we'll take that as the switch's limit for power dissipation. Sending 10A through the switch would produce a drop of 500mV, which translates to 5W of heat.. a bit more than 10 times what it should probably do.

[sp838]

Thanks Mike. This makes sense. I am going to pass the main power through a relay and use this switch to open and close the relay.

Thanks again, merry merry happy happy joy joy,

-s

[sp838]

Another question: this switch appears to only be a momentary switch. I think I need one that "latches" on and off. I see you have one in green:

http://www.adafruit.com/products/482

Is it possible to get this on/off type switch in red? Or can the red one be modified to latch on/off instead of being momentary?

Thanks again,

-s

[adafruit_support_mike]

That's this one: http://www.adafruit.com/products/916

And yeah, it should be fine as a relay controller.

[sp838]

Thank for the link. I must tell you honestly, your site is a disaster. These switches do not appear under the "components and parts > switches and buttons" category:

http://www.adafruit.com/category/54_155

They are also not found under "Batteries & Power > Power Switch"

Nor do they appear anywhere under the "LED" category.

I found the green on/off switch with a google search, and the related products listed below it are not other on/off switches in other colors, which is what one would expect, but instead suggests momentary switches, making no mention of the other on/off switches:

http://www.adafruit.com/products/482

For some odd reason, all of these are buried in the "sensors" category.

You guys should probably look into making your site easier to navigate and better categorized, currently it's a total mess.

Thanks again,

-Simon

[adafruit_support_mike]

**glances around**

Just between you, me, and every search engine on the planet, we have a team working on something very much like that.