Hi guys.
As a noob to building an amplifier, I read Space2000's warning about mosfets carefully. Not because of the particular mosfet he was describing but because it dawned on me that I do not know what is sensitive to handling nor how to improve my chances of success in assembling my F5T kits.
The soldering iron, esd strap, conductive mat were all touched on but briefly. I do not want to trash parts during assembly. So... my question is: What would be an ideal setup for safe electronic work with regards to esd, etc?
Thanks in advance!
As a noob to building an amplifier, I read Space2000's warning about mosfets carefully. Not because of the particular mosfet he was describing but because it dawned on me that I do not know what is sensitive to handling nor how to improve my chances of success in assembling my F5T kits.
The soldering iron, esd strap, conductive mat were all touched on but briefly. I do not want to trash parts during assembly. So... my question is: What would be an ideal setup for safe electronic work with regards to esd, etc?
Thanks in advance!
Here was me about a year ago collecting every piece of conductive foam, anti-static bag, and the like small bits of foam leftover from opamps, new computer parts (don't throw out the bag!), and I have this mishmash of stuff. I also have a telephone cord like thing that I picked up at an electronics and gadget show in China with an alligator clip to clip to your sleeve.
Then I met and I learned from a pretty knowledgeable gentleman that so long as you keep sensitive components in aluminum foil, it works pretty good. He stores them, handles them wrapped, and lays them out on a small sheet of aluminum foil.
I asked the reasoning behind this and it was to keep the difference in potential between the separate pins equal (or at "zero"). This is what conductive foam does as the aluminum foil is in contact with all the pins and surfaces of the transistor. He hasn't lost one yet in all his years. When he works on them, they are laid out on the aluminum foil he stored them in (touch the foil to get to the component). It also keeps it thin and less bulky than conductive foam and you can make the sheet as large or small or shaped to your needs. When you handle the foil, you have equalized the charge between you and the foil and no zapping of individual components.
Keep your feet on the floor and have some humidity in the air like flg says and I think you you will have 99.9% of what you need.
Makes sense I suppose.
PS -- I have since got rid of all the small, beat up, well used, pieces of conductive foam and krinkled antistatic bags I had. I now have more room for components (ugh!).
Then I met and I learned from a pretty knowledgeable gentleman that so long as you keep sensitive components in aluminum foil, it works pretty good. He stores them, handles them wrapped, and lays them out on a small sheet of aluminum foil.
I asked the reasoning behind this and it was to keep the difference in potential between the separate pins equal (or at "zero"). This is what conductive foam does as the aluminum foil is in contact with all the pins and surfaces of the transistor. He hasn't lost one yet in all his years. When he works on them, they are laid out on the aluminum foil he stored them in (touch the foil to get to the component). It also keeps it thin and less bulky than conductive foam and you can make the sheet as large or small or shaped to your needs. When you handle the foil, you have equalized the charge between you and the foil and no zapping of individual components.
Keep your feet on the floor and have some humidity in the air like flg says and I think you you will have 99.9% of what you need.
Makes sense I suppose.
PS -- I have since got rid of all the small, beat up, well used, pieces of conductive foam and krinkled antistatic bags I had. I now have more room for components (ugh!).
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Yeah, but the tinfoil hat has to be the handmade woven hat that has been braided in the Alpine mountains on a half moon night though. That is the best time to create Faraday cages.
But, it really does work... the storing of components in aluminum foil -- not the tinfoil hat (do they actually still make tinfoil for consumer use?).
What you are creating with the aluminum foil and components/chips/transistors inside of it is a Faraday Cage when you think about it...
http://en.wikipedia.org/wiki/Faraday_cage
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Wow! Awesome responses. Thanks everyone. I had been in the habit of touching the cases of the computers I am destroying for the same reason of coming to the same potential so what you guys have said makes perfect sense. Never thought about the aluminum foil approach. Pretty creative. I have a few inexpensive irons but nothing exotic and was looking to pick up a soldering station for this project. Given Space2000's adventures, I want to ask if there is a particular grade of soldering iron? PS I already have the tinfoil hat 
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I have heard people on few forums rave about Metcal soldering stations, but never have seen one for sale in any of the electronics stores in Toronto (the biggest city I am close to). Most of the local stores here in Ontario and Upstate New York (I have been known to cross border shop) usually carry Weller or cheaply made ones that don't last.
I am using a plain old light blue Weller 25 Watt soldering iron (with replaceable heater in case it breaks down), a fine pencil tip, an old springy iron holder I picked up somewhere, a sink sponge, a brass Curly Kate pot scrubber, and a mat. The Weller serves my purposes, rapidly heats up, and tips and parts are easy to find. Some 63/37 solder makes it easier yet (for me at least).
I am using a plain old light blue Weller 25 Watt soldering iron (with replaceable heater in case it breaks down), a fine pencil tip, an old springy iron holder I picked up somewhere, a sink sponge, a brass Curly Kate pot scrubber, and a mat. The Weller serves my purposes, rapidly heats up, and tips and parts are easy to find. Some 63/37 solder makes it easier yet (for me at least).
The gate of a MOSFET is extremely thin. Perhaps only a few molecules thick, and measured in angstroms. High voltage (like static electricity) will literally blow a hole through the gate oxide (you can probably find microscope pics of this on the web). Static electricity on a dry winter day can approach 30kV. The gate is no match for that!
All the ESD equipment simply helps to keep everything at the same potential. The "telephone cord like thing" should have a conductive wrist strap on one end, and the alligator clip connects to a ground point. NOT to your sleeve (and if you really want to get in-depth, don't wear synthetic fabrics while working with FETs). The cord should be made with a high-value resistor inline for safety purposes (else it wouldn't be pretty if you touched a live wire).
The main thing you want to avoid is touching the FET leads. Leave the parts in their conductive storage until ready to solder. Then touch some grounded metal on your workbench (a PC case is good) before handling the transistor. You can touch the tip of the soldering iron to the same metal ground point.
All the ESD equipment simply helps to keep everything at the same potential. The "telephone cord like thing" should have a conductive wrist strap on one end, and the alligator clip connects to a ground point. NOT to your sleeve (and if you really want to get in-depth, don't wear synthetic fabrics while working with FETs). The cord should be made with a high-value resistor inline for safety purposes (else it wouldn't be pretty if you touched a live wire).
The main thing you want to avoid is touching the FET leads. Leave the parts in their conductive storage until ready to solder. Then touch some grounded metal on your workbench (a PC case is good) before handling the transistor. You can touch the tip of the soldering iron to the same metal ground point.
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Both ends have an alligator clip (why I didn't differentiate between the ends, front end same as back end) and you try to clip the other end to something like your metal table leg (I just stick a rare earth magnet from a disk drive on said table leg and clip to there since the table leg is too thick). I don't know what is inside of it, maybe there is a resistor or small sand bar in there, but I'm not opening it up to find out. At the total cost of 12 RMB at the time (13 years ago), I believe I could have bargained lower.
Wouldn't my sleeve/shirt in contact with my skin/body/person carry the charge as opposed to my body (a bad conductor)?
I haven't had any problems yet wearing synthetics or cotton and I don't much like wool.
I've build a fair number of amps and never had problems with static discharge. In fact I cannot remember any transistor failure during assembling. I also don't use any fancy sort of soldering station, just a cheap adjustable Weller.
IMHO it's the shorts that kill the amps
The problem with damage done by static discharge is that components might continue to work but might fail prematurely:
Basics of Electrostatic Discharge
see "Latent Defect" in the link above.
Thanks for your kind reference - however, I'm pretty happy with my knowledge that came with my phd in physics and from my experience that came with having worked in the research center of a rather large semiconductor manufacturer.
As long as nobody fears building amps as they could fail prematurely due to static discharge any second I won't stop anybody wearing wrist bands
I wonder what the Class Aand A/B amplifier builders did before the invention of wriststraps, tinfoil hats, and electrostatic discharge?
I am confident that somewhere along the line starting where everything starts out as a bucket of sand being melted to being packaged, shipped out, running roughshod down a very bumpy road, during a lightning storm, ending up at the a large dsitributor's warehouse only to be re-packaged by hourly paid unskilled labour, shipped out further afar in yet another lightning storm, marked up further, arriving either at the small electronics dealer an hour from my house, where it is parceled out and put into small ziplock baggies with labels, and repeating the process again going down the bumpy road to my house.
Or if it doesn't get to the the small electronics dealer down the road, the UPS guy decided to leave the 24 inch X 16 inch X 6 inch box of transistors, capacitors, vacuum tubes, and really cool looking sticker (that sticker in real life doesn't look all that cool, but pictures of the sticker on the website sure did) I bought on-line "hidden" underneath my front door mat in a light rainstorm where it ultimately got wet.
Then hearing from the lady across the road who saw the delivery and saying that the UPS guy dropped the box as he was trying to close the door to his truck and hoped that it wasn't anything breakable.
At times, I think that static electricity is the least of my worries.
I am confident that somewhere along the line starting where everything starts out as a bucket of sand being melted to being packaged, shipped out, running roughshod down a very bumpy road, during a lightning storm, ending up at the a large dsitributor's warehouse only to be re-packaged by hourly paid unskilled labour, shipped out further afar in yet another lightning storm, marked up further, arriving either at the small electronics dealer an hour from my house, where it is parceled out and put into small ziplock baggies with labels, and repeating the process again going down the bumpy road to my house.
Or if it doesn't get to the the small electronics dealer down the road, the UPS guy decided to leave the 24 inch X 16 inch X 6 inch box of transistors, capacitors, vacuum tubes, and really cool looking sticker (that sticker in real life doesn't look all that cool, but pictures of the sticker on the website sure did) I bought on-line "hidden" underneath my front door mat in a light rainstorm where it ultimately got wet.
Then hearing from the lady across the road who saw the delivery and saying that the UPS guy dropped the box as he was trying to close the door to his truck and hoped that it wasn't anything breakable.
At times, I think that static electricity is the least of my worries.
Does anyone now wonder why I said what I said in post #2? I could be wrong though. 45% relative Humidity could solve 99% of your problems? But, what about all the "statements" being put forth in this can of worms thread? Been there done that! Even the experts don't agree, so I'm not suprised. Buy a humidifier and do the silicon last! And enjoy your amp! Don't forget the protection diodes at the input. A big Zap right thru your pot knob, to the pot and #$%^&*!
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