pcb123 help.

[jrz126]

I'm using pcb123 to draw up a pcb, I'm having trouble with the autorouter. I have a total of 214 nets, but it cant route 6 of them. Is there a way to tell it to route these first?

Also, I want to place some holes to mount the finished board, but when I run the auto router, it places traces right on top of them.

I noticed the routing grid option, what size should I use for that? Is it possible to make it too small?
EDIT: Nevermind, I just answered my own question :roll:

BTW I just found this board last week and I love it . I just wish it was a little more popular...does anyone know of any other message board like this that have more people on them?

 

[chemelec]

my stereo is pushing 2.14 horsepower. Check it out at www.cardomain.com/id/jrz126

How do you figure that?
One HP is 746 watts, 2 14 Hp = 1596 watts.
And What is the point of that site? No Projects there that I see. Just popups.

 

[jrz126]

you gotta use the page tabs at the top and bottom. It's a free site, so they gotta have a lot of ads.

I know one hp=746 watts, I'm running 1600watts. of course thats the max output that the amps are rated for. I know it's not the true value, and the only calculations i did was take 1600 and divide by 746. But thats the (car) audio buisness. If the amp can push 1000w for a split second before blowing up, they'll slap that rating on it. Thats usually what the generic companies do though. (they say it's a 500W amp, but fuse is only rated for 20 amps. if you assume that it's running at 13.4 V, it would produce a max of 268w


I use that in my sig. in a car message board. i shoulda figured someone would question me about it here :roll:

 

[ante]

Agree, nothing with substance just popup crap! :x

Ante :roll:

 

[Nigel Goodwin]

(they say it's a 500W amp, but fuse is only rated for 20 amps. if you assume that it's running at 13.4 V, it would produce a max of 268w

No, it could CONSUME a maximum of 268W, output power would be considerably less - probably between 150 and 200W.

As you already know, car amplifier specs are just a laugh :?

 

[jrz126]

I thought that the amp would produce the 268w and the speaker/load consume it?

anyhoo, anyone know the answer to my 1st question?

 

[Nigel Goodwin]

I thought that the amp would produce the 268w and the speaker/load consume it?

That assumes 100% efficiency, which as I'm sure you're aware is impossible!. The amplifier might be 80% efficient, losing 20% of the output power as heat - but the switchmode PSU will probably be about the same, losing 20% of the input power as heat.

I can't be bothered to calculate 80% of 80%, which is why I gave the figure 150-200W 8)

 

[Exo]

And the speakers themselves are also not 100% efficient...

 

[Nigel Goodwin]

And the speakers themselves are also not 100% efficient...

A long, long way from it! - but that doesn't affect the power output from the amplifier, just the acoustic output from the speaker.

I would have thought speakers in a car are particularly inefficient, due to their relatively small size and small enclosures (where fitted)?.

I once demonstrated a pair of very cheap 1x12 PA speakers I was selling, they were rated at 50W each and were the cheapest you could buy - I fed them from my Leak Stereo 70 amplifier, which gave an honest 35W RMS per channel, at low distortion (for it's day). In the fairly large bedroom at my parents it was well above the threshold of pain!, without turning the amplifier up particularly load - in a car that level of volume would not be possible (and still be in the car). BTW, the guy was impressed, and bought the speakers :lol:

I seem to remember conventional (not in-car) infinite baffle speakers are only between 5% and 10% efficient, ported ones 10% to 20%, and horn loaded ones 20% to 50%. A horn is simply an acoustic transformer, it matches the speaker cone to the outside air - making a huge efficiency difference.