PCB or point to point? - Page 1
Forum section: electronics / general

author: Connecteur
author_rank: Frequent Contributor
timestamp: September 26, 2020, 06:05:22 pm
content: For simple circuits without a large number of components, it it really worth the sacrifices of making a printed circuit board? It's easy to bend the leads and solder them together. The resulting shape can be bent to fit into a larger number of enclosures if needed.

author: daqq
author_rank: Super Contributor
timestamp: September 26, 2020, 06:39:56 pm
content: Depends completely on the situation, quantity of devices, quality expected (hobby one off prototype or thousands of pcs...) and a host of other factors.But given the price of professional PCBs these days and the simplicity of designing one... why not?

author: ogden
author_rank: Super Contributor
timestamp: September 26, 2020, 07:08:24 pm
content: You shall define what "simple circuit" and "large number of components" mean toyou. Yes indeed PCB is not always needed. Soldering few components together can do the job, also using perfborad is very popular for DIY circuits. Important rule: always make sure your circuits mechanically hold together well.

author: bob91343
author_rank: Super Contributor
timestamp: September 26, 2020, 09:57:47 pm
content: PCB is good for appearance and ruggedness. However there are pitfalls, particularly when currents are large, say over 100 mA or so.The old style terminal strips are still good in my opinion. Dead bug style is okay for testing but not for a permanent build.

author: Technomaniac
author_rank: Contributor
timestamp: September 26, 2020, 10:32:49 pm
content: About the time I went off the grid and had to make up a batch of charging regulators, I wasn't in the mood for photo-etching and I started making PC boards with my Dremel. The components are all on the foil side and the copper removal is done with a spherical tip. The result is rough looking, but can be done in record time. I would have done about 30 boards to date. Not so good when using chips as things get a bit close, but I DO have some with chips. Tracks can be scored with a miniature chisel-scraper but I haven't been doing that. Just a side note, I've noticed that the last batch of blank copper clad board I bought on eBay from China is thinner and so is the foil.I've made some very nice and very tiny boards with a CAD draughting program, you have to find one that allows you to change the thickness of the lines (tracks) to suit your requirements. I have a couple that do not and one that does. Then I print a positive film on an old HP laser printer with the knob turned up to print a heavier toner layer than normal. Exposure is done with a portaflood lamp at about a foot away, everything held firm in a hinged sandwich of glass and lid from an old photocopier.

author: tkamiya
author_rank: Super Contributor
timestamp: September 30, 2020, 03:35:21 am
content: I've built some fairly complicated circuit with point-to-point method. If it's one off or two, it really make no sense to do the circuit board. I do have a circuit that's simple but I use it over-and-over. I'm getting tired of making it by hand, so I may go PCB route.However, that changed when SMD got involved. Some recent and advanced chips only come in SMD. While it is possible, it is often not practical to air/hand wire these. Also, if it's high in frequency or stability/repeatability is important, PCB may be the only way.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 30, 2020, 04:20:50 am
content: Sure, no problem.The circuit being rather... amorphous, is more a curse than a blessing, I would say. They tend to end up like hairballs -- unserviceable. If you try to keep it flat and flexible (say using stranded wire to join rigid sections), well now the sections can flap around and short out. Obviously, some kind of fixturing would be helpful. (Wouldn't it be great if we wove everything around an insulating board or something?)It's also useless for any kind of bandwidth. An audio amplifier is probably okay. A switching supply is probably not. Digital logic, who knows. Microcontrollers, wouldn't bet on it -- a small thing will probably work, sure, but how much can you hang off it before it starts going bonkers?The next step up, I suppose, is pad-per-hole or strip board, whatever kind you like. Still free-form and lacking ground, but at least the board and holes enforce some structure -- if you don't cram things together, it stands a good chance of being serviced. You can draw extended grounds around signal routes, if you don't mind wasting a lot of solder and board area. You can also get the stuff with ground plane, which is very attractive actually (if you take the time to look for it -- it's a somewhat unusual variety and probably more expensive).The step after that, is probably dead bug and such. Dead bug I think refers more to gluing down DIPs and hanging components off them. I never liked this exact method. It leaves too much height off the plane, the pinouts are confusing, you can't read the part numbers, and you don't have much way to make new nodes.An easy improvement is Manhattan style: cut small chits of copper clad and solder or glue them down. Free tie point, insulated from the plane, and at a regular height above it. You can even stack them in multiple levels (as the name suggests, like Manhattan skyscrapers); though that tends to get fiddly.Finally, you can go full proto and cut traces out of copper clad, directly. I like to use a utility blade, making two angled strokes to cut a shallow v-groove. Others like to use abrasive saws, burrs, end mills, engravers, or, if you happen to have the luxury of an engraving mill you can make full on layouts. A small drill bit (preferably carbide -- use a drill press!) can drill holes to solder or swage copper wire or rivets, making vias to the back side ground plane.Even more advanced, I suppose, you can make multilayer boards of sorts, by laying down polyimide tape for insulation, then copper tape for traces. It's solderable, at least on top (the adhesive tends to be a bit annoying). Cut holes in the tape layers to expose solderable metal. Tape over anything you don't want soldered. The components on such construction are quite accessible (well, assuming you haven't buried any chip components in the stack!), but beware if you ever have to dig into the stack...yeah.Not fine pitch, the adhesive isn't that strong. But the broad traces of this method do lend themselves well to high current switching applications.Somewhere between these techniques, you'll find it's handy to use a mix of THT and SMT parts -- you can string an axial resistor between relatively distant pads, while you can place chip components between adjacent pads, whether cut into the board, or islands Manhattan-style.Tim