Please forgive me if this has already been asked in some way before. I’m new to this electronics thing and don’t quite understand what I’m reading on other posts that feel like they should be answering my question.
While I understand how to make schematics and am working through some tutorials on KiCAD, there’s one thing I’m not quite sure about which is how to create those holes to poke jumper wires or probes through on a single-layer PCB.
Will poking a hole through a tracer suffice, and with that what size should the hole be? Do I just leave a pad? Do I have to do something else? I read somewhere that I could use vias but I think that requires a two-layer PCB at least. I attached the drawings we’re supposed to make PCBs of.
A little bonus question, I’m using the 11.9mm-horizontal footprint for my THT resistors since I’ll be using 1-Watt resistors. Does that sound about right?
I’m sorry if this is all confusing or rookie as hell. I’m just really lost and would appreciate every bit of help I can get for this project. Uni hasn’t taught us shit about how to use software and while I feel like I can McGyver something akin to a PCB with a marker, I think it’d be better in the long term for me to learn KiCAD or some other piece of software.
I think a problem with your post is for everyone to be on the same understandable language so to speak.
Are you able to produce the schematic that you want in KiCad? If you are, you ought to be able to post that schematic instead of a photo of a hand sketch.
When you put resistors or other components in a schematic diagram, the components should eventually all be associated with a footprint. That association can be done later in KiCad, but it saves a lot of work it you make that association for your first resistor before copying it to put more resistors into the schematic diagram. Axial resistor footprints should include the two round through hole pads. Normally I would expect 1/4W to 1/2 W resistors to have lead spacing of 10 to 15 mm, but there are also high power density 1W resistors which may fit in a 12 - 15 mm lead spaced footprint.
You can check distributor websites (Mouser or Digikey in the USA to check the resistors that are available to get an idea about this. Allow adequate bend radius.)
Of course you might reasonably want to do this whole exercise using surface mount instead, such as using 1206 size resistors which are arguably MUCH easier to swap out on a two layer board which has plated through holes.
Firstly I wouldn’t bother with single layer PCBs if you’re getting them manufactured. Double sided is the norm now.
Depending on how you want to make contact with probes or jumper wires, for the footprints of those points you draw as open circles, you could opt for Test Point SM pads, TH pads with a PTH hole in the middle which you could touch with a probe or solder a wire to, TH pads which you solder pin connectors to, and many other possibilities. Have you thought about what kind of footprint you want?
Ah sorry about the language of my post but. I think I’m still a little too ignorant to be able put the problems or my thoughts on this properly into words.
We could probably consider a two-layer PCB but if I recall correctly, our instructor specifically told us to make all of this on a single-layer PCB, hand-etched using toner-transfer or whatever technique we’re comfortable with using on a copper sheet. That, and ordering a custom PCB where in the country I live is a bit costly and takes a bit more than a while and with this being the first time I’m making a PCB, I’m a bit scared of shelling out cash that might go to waste.
As for the footprints of the holes, I’m thinking of them being 0.9mm holes since that’s roughly the size of the feet of the THT resistors I have on-hand. I’m not sure about using pads for the test points since I sort of want the jumper wires to sit where I poke them.
The TH pads with PTH holes look to be about what I’m looking for though I’m not sure how I’d make the plating considering that my PCB might be hand-etched. Is there perhaps a way to solder a sort of terminal for me to poke a jumper or probe into and what might that terminal be called if I wanted to order a few?
Also, here’s the schematic I drew up for one of the circuits. It seems about right except for the voltage source which is mostly a placeholder since I need all 11 of those circuits to be on a single board powered by a single supply.
Thank you for the help so far and I love the puns!
Ok, but KiCad doesn’t have a “single layer” setting. What you can do is accept the default double sided setting, then not use either the top or bottom layer. If you will be using toner transfer, then just generate a transfer sheet for one layer.
Back in the day when I was messing around with icky chemicals like ferric chloride, I “tinned” the copper with a soldering iron and solder to cover the bare copper to protect from oxidation.
A possibility for the hole problem is to use (male header pins) soldered into the pads. You can then either wrap thin wire from one pin to another or you could purchase (female header pin jumper wires) to plug into the header pins.
Header pins come in strips and conveniently break into single pins when required.
Google the terms in brackets to see what I mean
The terminology for mounting components including resistors is to mount on your board “radially” (vertically) or axially (horizontally).
Possibly best to use jumper wires to join each experiment power supply to an input power supply off the board as joining all the power pins together will cause one layout to interfere with another layout. Use header pins each different Vs.
Use thick tracks (at least 2mm wide) and all pads at least 3mm diameter.
If it is not too rude a question, in what country do you reside?
I had another look at your top hand drawing.
If you place a power disconnect between Vs1 and R1 in your Thevenin / Norton equivalent circuit (middle left drawing) you could join all your Vs’s together, but you would only be able to use one proof at a time.
And header pins are usually sold in 40 pin strips.
As I said you have to think hard about how you will be connecting to the points indicated. You only have so many hands so test point pads for probes may be impractical. Pin connectors can take hook or crocodile clips, but you have to leave enough space around the pin.
BTW in your KCL schematic, one of the pairs of pads from the voltage source is redundant since they are in series.
@Lorence_Lacks
I picked on header pins because they are rigid, easy to solder, cheap and easy to find. If you have access to dead computer motherboards, you don’t even have to find a seller of these pins; just recycle the motherboard pins.
This thing is so simple that you could easily use a piece or plywood, acrylic or other sheet material. Then drill holes in it and add banana jacks and then solder the parts on the back directly between the banana jacks. Maybe add a small PCB if it needs a power supply.
But if you insist on making a PCB, treat the “holes” as just any other component. Add them to the schematic as test points, then assign whatever sort of connector you want as footprints to those schematic symbols. Then put all the footprints on the PCB and design it.
The only complication is that you have to decide on what those test pins look like. 4mm banana jacks are sturdy, but quite bulky and not very cheap. 2mm banana jacks are often of quite low quality. Things like the pins from single row headers are not very sturdy and therefore not fit for educational institution where they are likely to see some abuse.
