How do you "feel" circuits?

[Scott75s1974]

Maybe an odd question.

I'm impressed by how many folk on here can zero in on troubleshooting. From my limited beginnings in engineering, I can "feel" how physical structures like trusses and bridges work.

I'm not as good with circuits (never had training). I recall looking at a Scott schematic w/voltages for MONTHS trying to figure out why one side's bias was always low. Then it hit me that if the driver transistor was was short on gain, that would do it. Sure enough that was it. I can feel the flow in a circuit a bit in DC -- what transistors, resistors, diodes do. I can feel ohms law a bit. But I really can't feel ac or even more an audio signal going through it. I know what capacitors and inductors do, but really can't feel it at all.

So, how do you experience an audio circuit? How do the different components feel? Or if feel is the wrong word, how do you experience/imagine them?

Hopefully an interesting question. (Or maybe just me revealing synesthesia and thinking everyone has it.)

 

[El Rubio]

I think those “feelings” come from experience. I work in a very specialized field and recall crossing paths with a military installation. The military was easy to work with. The ‘hassle’ came from the communications contractor, a large company you would recognize. I emailed the engineering manager my findings and he sent one of his guys out to check it out. A day or two later he sent me a photo of his guy’s spectrum analyzer and tried to tell me something he detected ( not what I detected), was my problem and not his equipment. I could see the equipment settings in his SA photo would bury the signal I was referring to below the noisefloor of his device. I respectfully pointed that out and he wanted me to meet his tech onsite. They sent 5 engineers. They fully intended to make me look foolish. I had my ducks in a row and was able to show them their mistake. Me and the tech resolved the issue. Experience made me confident in that meeting and my observations were diagnosed relying mostly on experience and I was very confident in it. So, if I understand you correctly, I think those feelings are skills we gain from experience.

 

[chazix]

I like to think I've got the feel. Sure can't explain how I got it, though.

I think El Rubio has it about right. At least part of it - a big part - comes from experience. I reckon it's helpful to have plenty of experience with things that are not working, in addition to things that are perfectly working.

(Yeah, I know, This Post is Worthless Without Anecdotes. Stay tuned. Gotta think of one that makes me look smart. El Rubio set the bar pretty high.)

There are a couple of book-learning things that are I think are essential to having the feel. I think there are threads about that already, so I'm just going to plug my #1 fave: Kirchhoff's Current Law. "Where can the current be flowing?" is often the key question in diagnostic work, at least for me.

 

[avionic]

I just get the job done.

 

[Lavane]

It helped me to think of electronics like hydraulic systems. I worked for an agricultural harvesting machines manufacturer years ago. There are hydraulic valves, pumps, motors, check valves, flow control devices, hoses made for various pressures, etc. It dawned on me it was all kind of similar to electronic circuit designs.

 

[chazix]

(Edited to avoid a possible over-step on my part.)

If this thread turns out to have legs, maybe we could say that it's about "intuition" instead of "feel"? Subject to the OP's opinion, natch.

 

[Scott75s1974]

Thanks all. By "feel" I don't mean emotions, but imagining the forces in my head and feeling or visualizing (prob is you can't see it) what is happening in the circuit. After staring at the schematic for months, I could feel the low gain drag in that circuit and it clicked. This works for the pressure analogy. Kirchhoff's Current law (which I'd guess a lot of folk just intuit rather than know and name), certainly helps deepen the imagination.

 

[Scott75s1974]

If this thread turns out to have legs, maybe we could say that it's about "intuition" instead of "feel"? Subject to the OP's opinion, natch.

Intuition is a fine description. I'm interested in what the experts look for and how they know to look for it -- beyond just specific knowledge of issues with certain designs.

 

[SmileyFaceEQ]

Experience and knowledge of how things are supposed to work. I vividly recall my first time staring hopelessly at a PCB inside an ADC equalizer and being mesmerized by all the tiny components. Just yesterday I bought a Technics SU amplifier with a supposedly blown channel and had it running perfectly inside 30 mins. Same old tired process of dirty contacts and dry solder joints on the input jacks. IDK, sort of boring nowadays. I still have fun opening and cleaning wafer switches though.....the pucker factor is real.

Resources online like AK, Vinyl Engine, VINTAGE AUDIO ADDICT, Mr. CARLSON, TREVORS BENCH, XRAY TONY, JORDAN PIERS, ET. AL have provided me with countless hours of intruction and practical know how.

I completely disassembled a restored a Dual 1219 inside 2 hours on Saturday afternoon.

I know I still have plenty to learn and always loom forward to a new challenge.

 

[daveshel]

I've learned over the years that when I lose my keys or my glasses, it's a lot more effective to search for them in my head than wandering around the house looking. Where was I the last time I had them.

I've more or less adopted a similar approach to troubleshooting circuits, although it is somewhat less effective. But it's cheaper than an oscilloscope.

 

[kwayde]

I accidentally felt a circuit once that threw me across the room where I was lying on the floor wondering how the hell I got way over there.

 

[Scott75s1974]

I've been trying to think my way through various components.
For the harder ones: I can feel a capacitor as something like a non-diminishing tuning fork that can cancel out some frequencies and when properly wired, create certain ones. And thus an RC network. But there's a kind of threshold more than one resonant frequency. Have to switch to a bucket metaphor for that. And my ability to feel it diminishes rapidly.

Edit: prob better to think of it as an organ pipe for the pressure flow analogy.

I realize I'm saying "feel" because this stuff ain't visible.

 

[crispycircuit]

1st make sure you have a 100 volts or more, then stick your finger in it!

 

[KKnight]

I just get the job done.

You USED TO get the job done. Now you just live in this forum..