Super simple things can still be drawn with a Sharpie if you need something fast and ugly. When I said simple, I meant 4 diodes and 4 big electrolytics kind of simple.
I began to make my own PCBs in a time and place with no Sharpies.
So I would design my PCB by hand, with a pencil, on 0.1" grid graph paper. Once the design was complete, I would tape the paper down on the copper clad board and use a nail (didn't have an awl) to make a tiny dimple in the copper at every hole location. Then remove the paper, and connect the dots with resist, by hand, using the dimples in the bare copper board, and the drawing on graph paper, to reproduce the track pattern.
And the resist? Ordinary household oil-based paint. The special resist-pen consisted of an ordinary ball point pen that had run out of ink and was ready to throw away - I would pull out the metal tip, poke one of my mother's sewing needles in from the ink side, and pop out the tiny little ball at the tip. With the ball removed, you had a very fine nozzle. Now suck some oil paint up into the refill, and there is your free, custom, hand-made PCB resist pen!
As with most things, the more you use a technique, the better you get at it. In my early twenties I laid out and built an entire stereo Dolby B board using this method for example, and an entire audio function generator based around a quad op-amp that I ended up selling to my college physics lab. I used the same technique to build multiple fairly complicated audio power amplifiers, including some later ones based on integrated circuits. Circa 1988 or 1989, I remember designing and building an audio amp for a classmate using a pair of TBA810 chips, configured in bridge mode so he could get more power.
Necessity is the mother of invention...when you don't have fancy tools or the money to get them, you find ways to work with what you can get your hands on.
And there are always benefits to such approaches. I think designing so many PCBs entirely by eye left me with a much better ability to connect a schematic drawing with a physical layout, and vice versa. Standing parts like resistors on end let me shrink my PCBs to very small sizes compared to today's computer layout software - a vital feature, since I had no money, and bare copper-clad board wasn't cheap. I had to make every square inch count.
I'm too lazy to make PCBs any longer, and often solder components directly onto protoboard. I virtually never plan a layout in advance, simply place parts and solder, one part and one connection at a time, until the circuit is complete. Apparently my brain can still connect schematic and physical layout pretty well, because the stuff always works after I finish it, usually with very little debugging and few or no mistakes found.
As a "for instance", not long ago I built a guitar (speaker) cab emulation filter using multiple op-amps and a JFET or two. I designed the circuit using LTSpice, and built it straight onto proto-board. It's a fairly complex set of adjustable filters that roughly reproduce the intentionally far-from-flat frequency response of a typical guitar loudspeaker. I crammed the whole thing onto a tiny protoboard probably no more than 2"x3", with space left over.
I couldn't find that little protoboard today, but here are a couple of images of another circuit I designed, simulated, and built straight onto proto-board a few years ago. Four active devices and a fairly complex filter producing an EQ curve for a custom guitar amp - and it all fits on one-half of a 2"x3" proto board!
-Gnobuddy
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