Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: bulkhead on December 19, 2007, 01:05:09 PM

Title: switch ratings...voltage and current
Post by: bulkhead on December 19, 2007, 01:05:09 PM
Is there a difference between a switch rated for 12V DC and 25A and one rated for 120VAC and, say, 2.5A?  If I go with the 120VAC switch, but I use 24V DC, can I have a larger current?  Does it work this way?

On another note, what happens if the current exceeds the switch's rating?  Does the specified current indicate the maximum current that can pass through the switch, or that can be switched on/off?  I plan to use this switch as a "kill switch" for a robot, but offhand I can't find one with a large enough current rating, although 95% of the time theres probably a very low current when the switch is actually used (unless the bot malfunctions and needs to be shut off while driving full speed).
Title: Re: switch ratings...voltage and current
Post by: HDL_CinC_Dragon on December 19, 2007, 03:54:30 PM
You cant just use a circuit breaker depending on how big your bot is. The current rating of switches I think usually means how much can flow through it before I melts the switch... not 100% sure though...
Title: Re: switch ratings...voltage and current
Post by: airman00 on December 19, 2007, 04:17:10 PM
You cant just use a circuit breaker depending on how big your bot is. The current rating of switches I think usually means how much can flow through it before I melts the switch... not 100% sure though...

yep, basically the current rating is how much it can handle before breaking the switch ( aka melting the contacts inside the switch)