Sorry for the slightly off-topic thread. A question for those of you who enjoy playing with less modest voltages and currents.
I'm thinking about making a resistive dummy load with switchable Z - 4/8/16R using 2 x 10W 8R2 resistors and a on-off-on DPDT. I don't really need the switchable Z, but if I'm going to go to the trouble of getting the soldering iron out, I might as well make a project of it and give myself a little bit of future proofing.
10W resistors can easily cope with the 2W my amp should be able to deliver. However, what about the switch?
I realised that I hadn't thought about this sort of thing for quite some time. If an amp is putting out e.g. 1W of clean signal into an 8R speaker, then the average (or whatever) voltage = Sqrt(1W*8R) = 4V and the average current = Sqrt(1W/8R) = 0.35A. Most switches are happy with a few A, so I should be good to go. Am I correct?
I wouldn't even hesitate. wait a minute - what type of switch?
Good point - I have a buch of fairly typical sub-miniature toggle switches rated, as far as I can tell: 2A @ AC 250V; 5A @ AC 125V; 5A @ DC 30V
all your switch ratings are greater then yr amp ratings. what could possibly go wrong? don't the ratings only apply with inductive loads?
I can never remember; is sub-minature smaller than minature, or not quite minature? sub-sahara, sub-tropical, the sub prefix tends to confuse me.
QuoteSorry for the slightly off-topic
I don't understand switch nomenclature either - they are the typical size switches we use, not the really tiny ones that you might cram in a 1590A.
I'm not really worried about this and I'll use one anyway. I guess I was just (i) over-thing it - mostly because I don't understand the power ratings of the switches and (ii) was wondering if my math is correct and what the signal going into a cabinet looks like in terms of V and A.