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#21
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"Joe" wrote in message link.net...
"Tom Bruhns" wrote in message ... .... Easy enough to use SMT components soldered to a piece of copper-clad for a ground plane. Just put down the two caps and the shunt resistor "tombstone" style, ... Joe: "I don't even know what you mean by 'tombstone style'," Tombstone style...just solder one end to the copper-clad board, and the other end sticking up in the air. Looks like a micro-size tombstone sticking up from the board. .... Cheers, Tom Hi Tom, Being so new at this, I don't even know what you mean by 'tombstone style', and it sounds like an awful lot of work to be scoring pcboard with an Xacto knife to create transmission line effects. It's really not all that difficult. Just use a ruler to guide the knife, use a sharp knife, and the strips you want to remove can usually just be pulled up in one piece (each). Or do it as Ian suggested, with sticky copper tape. As Ian wrote, keep lead lengths extremely short, like "zero." He suggested putting a piece of heavy copper wire through the board where you want to connect to the ground plane. Another way is to simply drill a hole through the board and drop an 0805-size surface mount part into the hole, and solder both ends. A 1/16" hole would work, but you'd do better to pick a size that just fits the part you want to use. Not all 0805 parts are quite the same size, but the body lengths are pretty accurate and work nicely in 1/16" thick board material. Any of the methods mentioned by Ian and myself will work well, and all are reasonably easy to implement with a bit of practice and patience. Cheers, Tom |
#22
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Tom Bruhns wrote:
Any of the methods mentioned by Ian and myself will work well, and all are reasonably easy to implement with a bit of practice and patience. One method of "etching" that worked for me was using a reamer bit on a drill press to cut through the copper and barely into the PCB material. This has the advantage of leaving a ground plane in between the active traces. Also great for scouring and sizing PCBs. -- 73, Cecil, W5DXP |
#23
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On Wed, 06 Oct 2004 12:20:57 -0500, Cecil Moore
wrote: Tom Bruhns wrote: Any of the methods mentioned by Ian and myself will work well, and all are reasonably easy to implement with a bit of practice and patience. One method of "etching" that worked for me was using a reamer bit on a drill press to cut through the copper and barely into the PCB material. This has the advantage of leaving a ground plane in between the active traces. Also great for scouring and sizing PCBs. This is where those Dremmel tools come into their own! -- "What is now proved was once only imagin'd." - William Blake, 1793. |
#24
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Paul Burridge wrote:
Cecil Moore wrote: One method of "etching" that worked for me was using a reamer bit on a drill press to cut through the copper and barely into the PCB material. This has the advantage of leaving a ground plane in between the active traces. Also great for scouring and sizing PCBs. This is where those Dremmel tools come into their own! As a matter of fact, when I did this stuff at home, I used a Dremmel tool. |
#25
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Thanks all for the suggestions, I have a dremel, and this might be a good
project for me to learn how to use smt stuff. I will need to get a small lighted magnifier tho, cause my eyes ain't what they used to be, even with my reading glasses. Joe |
#26
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"Joe" wrote in message ink.net... Thanks all for the suggestions, I have a dremel, and this might be a good project for me to learn how to use smt stuff. I will need to get a small lighted magnifier tho, cause my eyes ain't what they used to be, even with my reading glasses. Joe Joe, If you are like me, you will want to use 805 or larger SM. 402 type drive me batty, and if you ever drop one on the floor, it is gone forever. Tam/WB2TT |
#27
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"Tam/WB2TT" wrote in message ... "Joe" wrote in message ink.net... Thanks all for the suggestions, I have a dremel, and this might be a good project for me to learn how to use smt stuff. I will need to get a small lighted magnifier tho, cause my eyes ain't what they used to be, even with my reading glasses. Joe Joe, If you are like me, you will want to use 805 or larger SM. 402 type drive me batty, and if you ever drop one on the floor, it is gone forever. Tam/WB2TT Hi Tam, Actually, the ones that looked easiest to use were the 1210 case size. I ordered some from mouser yesterday. I hope they're big enough for me to see. I was wondering about a post I read somewhere else a long time ago. Is there such a thing as a paste (that comes in a tube) that can be applied to the terminals of a surface mount device and then when it is stuck to the board, the paste hardens into something like hardened solder? So it is mounted to the board and soldered with this paste? Joe KB1KVI |
#28
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Joe wrote:
. . . I was wondering about a post I read somewhere else a long time ago. Is there such a thing as a paste (that comes in a tube) that can be applied to the terminals of a surface mount device and then when it is stuck to the board, the paste hardens into something like hardened solder? So it is mounted to the board and soldered with this paste? One-part conductive epoxy fits that description. It's commonly used to mount SMT parts on hybrid circuits. However, the ones I'm familiar with require curing at an elevated temperature (e.g., 150C for an hour). I believe there are also some UV curing conductive epoxies. Conductive epoxy can be used for mounting parts on a PCB, too, but I don't think it's commonly done because it's considerably more expensive than solder. There might be two-part conductive epoxies that cure at room temperature, but I've never used one and am not sure they exist. The one-part epoxies I've used aren't conductive until they're cured -- the tiny conductive (gold or silver) particles in the paste don't contact each other until the curing process causes the epoxy to shrink and pull them together. Then there's solder paste, nearly universally used for mounting parts on PCBs. This also fits your description and can by applied by hand with a syringe, then melted by a number of means -- hot air, IR, soldering iron. It's actually a slurry of flux and tiny spheres of solder. It's not really sticky, but sort of gummy, so some other means (like superglue) has to be used if the parts need to be kept in place when the board is inverted or severely disturbed before the paste is melted. Roy Lewallen, W7EL |
#29
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"Roy Lewallen" wrote in message ... Joe wrote: . . . I was wondering about a post I read somewhere else a long time ago. Is there such a thing as a paste (that comes in a tube) that can be applied to the terminals of a surface mount device and then when it is stuck to the board, the paste hardens into something like hardened solder? So it is mounted to the board and soldered with this paste? One-part conductive epoxy fits that description. It's commonly used to mount SMT parts on hybrid circuits. However, the ones I'm familiar with require curing at an elevated temperature (e.g., 150C for an hour). I believe there are also some UV curing conductive epoxies. Conductive epoxy can be used for mounting parts on a PCB, too, but I don't think it's commonly done because it's considerably more expensive than solder. There might be two-part conductive epoxies that cure at room temperature, but I've never used one and am not sure they exist. The one-part epoxies I've used aren't conductive until they're cured -- the tiny conductive (gold or silver) particles in the paste don't contact each other until the curing process causes the epoxy to shrink and pull them together. Then there's solder paste, nearly universally used for mounting parts on PCBs. This also fits your description and can by applied by hand with a syringe, then melted by a number of means -- hot air, IR, soldering iron. It's actually a slurry of flux and tiny spheres of solder. It's not really sticky, but sort of gummy, so some other means (like superglue) has to be used if the parts need to be kept in place when the board is inverted or severely disturbed before the paste is melted. Roy Lewallen, W7EL Thanks Roy, It sounds like the solder paste is what I heard about. Sounds easier than trying to solder such small parts with an iron. I will see if mouser carries it and give it a try. Joe KB1KVI |
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