Help with Component Retailers !?!?

[faithblinded]

Hello all, I'm in the process of building an electronic firing board for my fireworks show this year. Being my first semi complicated forray into building my own circuit, I am at a loss as to where to find some of my needed parts.

I have been to a number of different component retailers on the web and failed to find one component in particular. This is a cry for help.

The one thing I can't find anywhere for less than 35 bucks(way expensive I think), is a single pole, non shorting, 7 or more position rotary switch at least 5A@120VAC. I found one but it was sooo ridiculously priced.

Some of the other things I need for my project:
100+ - 50PIV diodes
3 - red panel lights, 12VDC 10-30A
8 - SPST Off (on) momentary push button switches 6A@120VAC
15 - 5mm LED's and chrome holders
3 - DPDT center off toggle switches 10A@120VAC
Aslo some assorted resistors and connectors I shouldn't have any problem getting most anywhere.

The sites I have been to:

http://www.allelectronics.com/index.html - good site with alot of the stuff I need, not the rotary though... seems like pretty good prices

http://www.digikey.com/ - their catalog is a pain in the butt to surf, and they seemed a bit expensive. hard time findin things I need, not familiar enough with manufacturers. I prefer a surfable catalog index.

http://www.bgmicro.com/ - their catalog is fairly ecclectic and unorganized, IMO, but they have a few things. small selection though...

http://www.jameco.com/ - nice web surfable catalog index, not an enormous selection, but not bad. prices seem ok. no rotary switch for me...

http://www.mouser.com/ - Huge catalog, siilar to digikey. Seemed a little easier to surf through than digikey. Their prices seemed average.


Those were about all I could find that would sell components in the small quantities I need. Now I need the experts around here to show this newb where to get the real deals... If anyone has a scoop on some rotary switches like I need, PLEASE let me know, I really don't wanna shell out 35 bucks a piece for 3 of em. I'll take links to any sites I missed, please...

Thanks for any help ahead of time!

[tiroth]

You should get the Mouser and Digikey paper catalogs, they are indispensable.

Why not use a cheap low-current 7-position switch to activate relays? Seems easier (and cheaper) than finding a rotary switch with such odd specs. Then you could probably source everything surplus.

Can I ask why you need mains voltage handling throughout your design?

[faithblinded]

ACtually it's an all DC circuit.

It will run on two sealed lead acid, 12V 7A batteries hooked up in series. This will give me 24V @ 14A I assume?

The reason the specs are listed in AC is because that's how they were listed on the site I pulled the schematic I modified from. I'm no expert, just starting to learn my DC stuff. (I'm only on chapter 3 of the DC textbook I'm readin LOL)

Are you suggesting I should use a low voltage rotary switch(thus cheaper), in conjuction with an isolated low voltage power source, to activate relays to control my 24V? That seems like an okay workaround....

Thanks for the quick reply, I really appreciate any help and suggestions, I'm an electronics retardo....

I'll see about getting the paper copies of digikey and mouser's catalogs. Seems like that would be a LOT easier to go through.

thanks again

[faithblinded]

Wow, now that I'm thinking about it, that would allow me to replace the expensive momentary switches as well, with lower rated switches...

Now I need to redo my schematic tho LOL. O well, this could save me big money...

Thanks Again!!

[Bill Fitzpatrick]

Originally posted by faithblinded

It will run on two sealed lead acid, 12V 7A batteries hooked up in series. This will give me 24V @ 14A I assume?

No, it will give you 24v@ 7a

[faithblinded]

Ok, so should I use resistors to pull my low voltage control current from the 24V, or should I use a seperate power source?

[faithblinded]

oh ok

so if i ran them in paralell that would keep the voltage the same but add the amperage?

[tiroth]

Originally posted by faithblinded
ACtually it's an all DC circuit.

Good, I was a little afraid that the mains was being run all over the place.

The reason the specs are listed in AC is because that's how they were listed on the site I pulled the schematic I modified from.

Ok. I'm guessing you just need sufficient current handling then, and the voltage spec was well over-rated.

Without knowing the schematic it is hard to say, I wonder how much DC current is really flowing. The one thing you must watch out for is that it is much harder to interrupt DC current flow than AC current flow, so don't under-spec those relays.

Two 12VDC 7aH batteries in series will be a 24VDC, 7aH supply. That's amp-hours, not amps. You could use half the supply to power 12V relays, or the whole supply to power 24V ones.

[faithblinded]

Well since I have such an expert audience I have another question. I need to buy a decent soldering iron. I want to get a nice station, but don't wanna spend over 100 bucks. I don't need all the bells and whistles, just a nice quality station. Any recommendations?

[faithblinded]

Originally posted by tiroth


Two 12VDC 7aH batteries in series will be a 24VDC, 7aH supply. That's amp-hours, not amps. You could use half the supply to power 12V relays, or the whole supply to power 24V ones.

Ok, well, the run from my board to the firing stations in the field will be over 100 feet, which is why my system is 24 volts instead of 12. At 12 volts my ignitors would take too long to fire.

here's my ROUGH schematic, im not up on all my notation, and this is just the firing panel, without alot of documentation, mostly just for my benefit. I'll have to draw up a proper schematic by hand and post it so I can get some pointers.