Search found 134 matches

by Chris Foley
Tue Jul 01, 2003 4:52 pm
Forum: General Discussion
Topic: optical interrupt for rate of fire.
Replies: 4
Views: 2421

Re: optical interrupt for rate of fire.

The business with the two wires is a great idea, if your aim is good enough, and the wires are thin enough so as not to deflect the paintball or slow it down significantly. Use two taut 42 gauge magnet wires, with one end connected to ground, and the other connected to a 1K pullup resistor, Connect ...
by Chris Foley
Mon Jun 30, 2003 8:38 pm
Forum: General Discussion
Topic: optical interrupt for rate of fire.
Replies: 4
Views: 2421

Re: optical interrupt for rate of fire.

If you can get the paintball gun to trigger from an electrical signal, all you have to do is synchronize the firing with a strobe light, and you can determine speed by measuring distance between images. Place a yardstick on the wall behind the paintball's line of travel. Strobotachs can be set at a ...
by Chris Foley
Fri Jun 27, 2003 6:07 pm
Forum: General Discussion
Topic: Mimicking tube behavior with solid state devices
Replies: 5
Views: 1796

Re: Mimicking tube behavior with solid state devices

Can you be more specific about what you want to do?
by Chris Foley
Sat Jun 21, 2003 6:19 pm
Forum: General Discussion
Topic: Dual power supply with current limit
Replies: 8
Views: 2199

Re: Dual power supply with current limit

Hi, Rogerio. From what I hear you saying, you need one or two sourcing/sinking switchable voltage/current sources, which can supply from -30 to +30 V in voltage mode, and -1.5A to +1.5A in current mode, controlled by a voltage/current switch and an external ramp signal? This is what you have in a st...
by Chris Foley
Thu Jun 19, 2003 7:02 pm
Forum: General Discussion
Topic: mosfet pinout?
Replies: 4
Views: 1247

Re: mosfet pinout?

If you just need a summary data sheet with pinout, try the NTE Semiconductors Cross Reference page<p> NTE Semiconductor Cross Reference Search Page <p>they have data sheets on the IRFZ44<p> NTE2395 -- Equivalent to IRFZ44 <p>and the MTP2955 in the TO-220 case<p> NTE2371 -- Equivalent to MTP2955 <p>Y...
by Chris Foley
Sun Jun 15, 2003 4:34 pm
Forum: General Discussion
Topic: data books
Replies: 5
Views: 1664

Re: data books

Hi, Charles. Another source of data pages are the manufacturers' offerings on CD. They're much less expensive to produce than paper, cost less to ship, and still help the manufacturer toward the goal of always keeping their product within engineers' reach. They generally offer them free when they "p...
by Chris Foley
Wed Jun 11, 2003 8:10 pm
Forum: General Discussion
Topic: How do DC clamp ammeters work?
Replies: 4
Views: 1273

Re: How do DC clamp ammeters work?

Look at Allegro Microsystems for a wide selection of Hall effect switches and sensors.<p>http://www.allegromicro.com/
by Chris Foley
Mon Jun 09, 2003 12:38 pm
Forum: General Discussion
Topic: PCB prototyping.
Replies: 13
Views: 2547

Re: PCB prototyping.

desterline -- go to the website listed above. Download EasyTrax or Autotrax. Both will output files in Protel format. Both are suitable for hobbyists. EasyTrax was Protel's freeware offering to starving college students for years, and many board shops are accustomed to getting low-budget orders from...
by Chris Foley
Mon Jun 09, 2003 10:16 am
Forum: General Discussion
Topic: PCB prototyping.
Replies: 13
Views: 2547

Re: PCB prototyping.

Protel has free downloads for two of their older DOS (early '90s version) programs -- Autotrax v. 1.61 and EasyTrax, which has been their freeware offering in the past. I'm not sure if the downloadable version of Autotrax on their website is artificially limited, but I still use the full DOS version...
by Chris Foley
Wed Jun 04, 2003 8:30 pm
Forum: General Discussion
Topic: Where is antiqueradios.com?
Replies: 7
Views: 1637

Re: Where is antiqueradios.com?

Stuff happens. But, in the moments between the time the power goes on and the smoke escapes, we don't usually call it stuff. Happy hunting.<p>[ June 04, 2003: Message edited by: Chris Foley ]</p>
by Chris Foley
Wed Jun 04, 2003 6:37 pm
Forum: General Discussion
Topic: Where is antiqueradios.com?
Replies: 7
Views: 1637

Re: Where is antiqueradios.com?

Is it possible you're looking for<p>http://www.antiqueradio.com/
by Chris Foley
Mon Jun 02, 2003 6:40 pm
Forum: General Discussion
Topic: most useful books
Replies: 14
Views: 3293

Re: most useful books

Data Books and App Notes -- especially Linear Applications Guide from National Semiconductor. It's a good beginning course in op amps and other linear stuff. Also, I'll second the motion on Don Lancaster -- all of his books are not only worth reading, but well worth the price. Active Filter Cookbook...
by Chris Foley
Mon Jun 02, 2003 4:54 pm
Forum: General Discussion
Topic: DC amps versus AC amps
Replies: 6
Views: 1846

Re: DC amps versus AC amps

Sounds good -- that's pretty much what I was thinking.
by Chris Foley
Mon Jun 02, 2003 1:30 pm
Forum: General Discussion
Topic: DC amps versus AC amps
Replies: 6
Views: 1846

Re: DC amps versus AC amps

The short answer is, you don't. Inductive DC loads will tend to draw a spark as the contact is breaking (Lenz), which deteriorates the mating surfaces of the switch, making them resistive and eventually causing them to fail. This tendency is overcome with switches which are designed to switch DC by ...
by Chris Foley
Sun Jun 01, 2003 9:03 pm
Forum: General Discussion
Topic: source for bulk LED's / Photocells
Replies: 4
Views: 1738

Re: source for bulk LED's / Photocells

All Electronics is a good source for surplus photocells. They have several parts available with different on/off resistances and sizes. They quote a price of $0.75 ea. in unit quantities, 0.60 in 10 qty. I'm sure if you call 'em up and talk with them, they'll be willing to go below your max price (i...