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Re: DIY SMT solder stencil making
开云体育I know you said you don’t have access to cnc, but highly consider buying a laser diode engraver from banggood or ebay or whatever.I have a 2.5w laser module connected to my ?desktop cnc mill. I spray a black spraypaint on my pcb, then laser away the paint. Etch and done. I also drill my pcbs with my mill in the same operation. For stencils I use kapton tape and the laser. Smear some solder paste onto the kapton and peel off, leaving the pads covered in solder paste. Works quite well. If you forgo the drilling, a laser engraver will do. On 25 Jan 2021, at 12:28, Leon via groups.io <leon355@...> wrote:
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Re: DIY SMT solder stencil making
Muriatic acid is hydrochloric acid, often called Spirits of Salt here. Amazon sells it, as do most hardware shops. Leon On 25 January 2021, at 10:06, David Slipper <softfoot@...> wrote:
Hi, I need a way to make small cheap SMT stencils at home - I do
not have a CNC or have access to one so I would prefer the toner
transfer and etching method that seems popular in some quarters. I loved the idea of using the thin aluminium of a drinks can but he uses a mixture of Muriatic Acid and Hydrogen Peroxide and I have found Muriatic Acid rather hard to find in the UK. Has anyone used this technique ?? How good is it ?? Are there alternatives to Muriatic Acid?? or where can I get it in the UK ?? What other DIY methods work well ?? Best regards,
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DIY SMT solder stencil making
开云体育
Hi, I need a way to make small cheap SMT stencils at home - I do
not have a CNC or have access to one so I would prefer the toner
transfer and etching method that seems popular in some quarters. I loved the idea of using the thin aluminium of a drinks can but he uses a mixture of Muriatic Acid and Hydrogen Peroxide and I have found Muriatic Acid rather hard to find in the UK. Has anyone used this technique ?? How good is it ?? Are there alternatives to Muriatic Acid?? or where can I get it in the UK ?? What other DIY methods work well ?? Best regards,
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EasyEda help needed
开云体育Can someone help me understand how to use EasyEda?? A friend found a module on there that I have been looking for.? I can load it into EasyEda.? I have both the online version and a stand alone version.? The standalone version asks for a storage location but appears to ignore it and save to cloud server.? I want to generate gerbers for the module that I assume is a public module (otherwise I could not have found it and loaded it) but I can't figure out how to "load it into pcb" as support told me to do.? They show options I do not have.? My assumption is that I have to have the project files which I do not have.? The pc board loads into the editor but I have few usable options.? I can save it as PDF, PNG, JSON, and a couple other formats but none are of any use for get it into a project (for any tool) or exporting gerbers for it.? How do I get the project and files? Can anyone point me in the right direction?Thank you. Jim Pruitt |
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Moderated
Re: Circuits on 2 sides
Thanks Donald, I will check that out.
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On 11/15/2020 10:19 AM, Donald H Locker wrote:
Have a look at |
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Moderated
Re: Circuits on 2 sides
P channel power FET, Drain to voltage input, gate to ground, source to circuit.? Your limit is the allowable gate to source voltage on the FET and current rating of the FET.
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Draw the bridge, put + and - on the AC and look at the output, now reverse + and -. Harvey On 11/15/2020 10:57 AM, Dave wrote:
That sounds like it needs me to go do some research on that one. :) I use a PTC fues for protection on the USB powered version but my other boards use battery power from 2.4 to whatever voltage but usually 3v max. And like I asked Bertho, does a diode bridge even work with DC? |
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Re: Circuits on 2 sides
Have a look at
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There are many sites with similar/identical circuits for reverse voltage protection. Donald. -- *Plain Text* email -- it's an accessibility issue () no proprietary attachments; no html mail /\ <> On 2020-11-15 10:57 a.m., Dave wrote:
That sounds like it needs me to go do some research on that one. :) I |
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Re: Circuits on 2 sides
Think of "I don't care which way the power got plugged in" as AC.? Think of power to your circuit as DC from the bridge. For battery circuits, that two diode drop can be significant, even if you use schottkey diodes.
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Harvey On 11/15/2020 10:54 AM, Dave wrote:
I thought a diode bridge or bridge rectifier was to convert AC to DC. So does a diode bridge work on DC? |
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Re: Circuits on 2 sides
开云体育Ok, I will look that up to better understand that. I learn something new everyday. And that is a good thing. :) Thanks, Dave On 11/15/2020 10:02 AM, MVS Sarma
wrote:
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Re: Circuits on 2 sides
Cool. That is good to know. I am only familiar with things like rectifier bridges on auto alternators and magnetos.
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Thanks, Dave On 11/15/2020 10:00 AM, Tony Smith wrote:
Helps if you think of AC as DC that keeps getting it's polarity reversed. |
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Re: Circuits on 2 sides
People call it polarity independent powering? On Sun, 15 Nov 2020, 9:24 pm Dave, <theschemer@...> wrote: I thought a diode bridge or bridge rectifier was to convert AC to DC. So |
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Re: Circuits on 2 sides
Helps if you think of AC as DC that keeps getting it's polarity reversed.
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So yes, a diode bridge will let DC through, but one polarity will get flipped. Tony -----Original Message-----does a diode bridge work on DC? |
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Re: Circuits on 2 sides
TYPO: I meant fuse.
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On 11/14/2020 7:36 PM, Harvey White wrote:
That takes care of the power supply polarity to the board (you might want to investigate a P Channel FET for a power protection device, it works for reverse polarity as long as you don't exceed a negative input greater than the gate/source rating). |
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Re: Circuits on 2 sides
That sounds like it needs me to go do some research on that one. :) I use a PTC fues for protection on the USB powered version but my other boards use battery power from 2.4 to whatever voltage but usually 3v max. And like I asked Bertho, does a diode bridge even work with DC?
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Thanks, Dave On 11/14/2020 7:36 PM, Harvey White wrote:
That takes care of the power supply polarity to the board (you might want to investigate a P Channel FET for a power protection device, it works for reverse polarity as long as you don't exceed a negative input greater than the gate/source rating). |
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Re: Circuits on 2 sides
I thought a diode bridge or bridge rectifier was to convert AC to DC. So does a diode bridge work on DC?
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Thanks, Dave On 11/14/2020 6:08 PM, Bertho wrote:
Dave, |
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Re: Circuits on 2 sides
That takes care of the power supply polarity to the board (you might want to investigate a P Channel FET for a power protection device, it works for reverse polarity as long as you don't exceed a negative input greater than the gate/source rating).
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It doesn't help the LED on the board at all.? I'm assuming more on the board than just a resistor and LED, though. Harvey On 11/14/2020 7:08 PM, Bertho wrote:
Dave, |
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Re: Circuits on 2 sides
Dave,
The easy, foolproof way is to add a diode bridge and it does not matter how it is plugged in. The drawback is that you have two extra diode voltage drops. Bertho |
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Re: Circuits on 2 sides
Sounds like you've got the right attitude and plan, then. Keep it up.
Donald. -- *Plain Text* email -- it's an accessibility issue () no proprietary attachments; no html mail /\ <> On 2020-11-14 4:09 p.m., Dave wrote: Donald,[snip] |
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Re: Circuits on 2 sides
Donald,
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? Of course doing it right the first time is the plan. I was just asking noob like questions just in case there was a use for that. I used to (and still do a little) program software and I have loads of REM statements so I don't forget what I did. But working with a team of developers or for a company that makes software is where it is even more important. I have formulas in my notes explaining what I used and why math in the software was done as it was. etc. But nobody is ever likely to see my code except the hackers. :) Now back to my pcb... I use red for positive and black for negative and have and will continue to have the info on my pcbs when they are made. The first one (the only one) that I have had made has the + and - a little small, but its there. I like the JST connectors as they are keyed and that is why I bought them. So with what I have learned is useful for other uses of the jumpers and non-keyed stuff. Lets say instead of a variable resistor I could have different brightness of some led's if the jumpers were switched to a different resistor or set of resistors. Thanks, Dave On 11/14/2020 2:15 PM, Donald H Locker wrote:
I would still strongly recommend a polarised connector. Somewhere down |
Leon
Steven Greenfield AE7HD
Bertho
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