[AMPS] Re: Power Handling of Resistors

[Jon Ogden]

on 3/9/00 11:36 PM, Carl Clawson at cclawson@transport.com wrote:

> Passing 1500 watts through closed terminals of the band switch doesn't
> dissipate 1500 watts in the switch or it would shortly be toast. We hope the
> 1500 watts makes it to the antenna.
> 
> Actually, we don't pass power through switches, we pass current through
> them. The switch doesn't know what the voltage on the load is. So the
> comparison is not very useful.
> 
>> I don't doubt that it takes 500 Joules to melt brass.  But for how long a
>> period of time does one need to apply the energy to make it melt?
>> 
> You'd need to dissipate the energy in the contacts before they could get rid
> of it by conduction or convection. My gut feeling is that anything under
> about 0.1s would be short enough for maximum temperature rise and meltage.

OK.  You're correct.  Understand now what you are saying.  Certainly you are
correct when it comes to how much power one could actually dissipate in the
switch.  No doubt about that!

Thanks for clearing that up!

73,

Jon
KE9NA

-------------------------------------
Jon Ogden
KE9NA

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."


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