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Metalmann

Joined Dec 8, 2012
703
.."and they have no idea how to adjust them manually. Everyone just hit's that stupid "auto-scale" button and wonders why it doesn't work."


Before retirement, we had several "Machinists" come through the plants, who didn't know how to set-up, and operate; manual Machine Tools.

Especially, Lathes, Mills, Welders, and Grinders.

If the machine did not have a keyboard installed, mostly they would stand around doing absolutely nothing, until someone else repaired their machines for them...

They were classified as Machinists, but they were well known as "Button Pushers"; and various other, not so nice, endearing, titles.;)

It bugged me too, DerStrom.

They were not safe to work around.

They knew programming, but not the required basics, of repair or maintenance.
They didn't want to get their hands dirty.
 

WBahn

Joined Mar 31, 2012
29,979
Unfortunately the standard check valve symbol used for a diode, is based on Ben Franklin's assumption that electron flow was from +ve to -ve.
Hence it being technically backwards facing.
Anyone that came through the tube era often intuitively tends to think in electron flow (cathode to anode).
Max.
The standard check valve symbol I always saw when I was working hydraulics looked like a ball in a sideways V. But as I go out and look now, I definitely see a symbol much more like the electronic symbol. Maybe the military used the one I was familiar with for some reason (such as teaching people with an 8th grade reading level how to maintain high-performance aircraft).
 

WBahn

Joined Mar 31, 2012
29,979
I can think in both, but I suspect if you come across a tube circuit you think in terms of electron flow, no?
Max.
I can work in both, but if I have a device that really calls for thinking of electron flow, I find that I will think of electron flow for that device and conventional flow for the rest of the circuit and not find it at all confusing. But if I have to analyze a simple circuit using electron flow I find that I have to be very explicit in what I do to avoid screwing up.
 

WBahn

Joined Mar 31, 2012
29,979
What drives me crazy is students at the uni who have access to the school's digital scopes, and they have no idea how to adjust them manually. Everyone just hit's that stupid "auto-scale" button and wonders why it doesn't work when the trigger is off. I always try to encourage them to adjust the knobs by hand and change the scales to make it look the way they want it to. I can't stand it when students insist on using the auto-scale button instead of learning how the scopes actually work.
I couldn't agree more -- and it is a complaint I have made time and time again. When I was a Physics undergrad, the test equipment we had available was antiquated and temperamental -- you spent half the time figuring out how to trick it into working (or outright repairing it). That was very arguably the most educational part of most of the labs!

It amazes me how many working engineers have absolutely no idea what the Hold Off control is on a scope. If the Auto Set doesn't do it for them, they are lost -- and aren't even willing to play around with the settings for fear of "messing something up". Sheesh.
 

ErnieM

Joined Apr 24, 2011
8,377
I somehow made the connection for anode and cathode in a diode years back. It's a handy reminder:


Once I "saw" the connection I can see it in schematics right away.

The only other "cool trick" like this I know of goes back to when TO-3 transistors were plentiful: if you hold them pins up with the leads closer you almost have a baseball field (2nd base is missing). If you start from home plate (the collector mounting hole) and run to first base... you're looking at the base pin. Obviously third is the emitter.

That's probably useless to anyone not from the US.
 

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GopherT

Joined Nov 23, 2012
8,009
is there any parts out there that uses the electron flow instead of the conventional flow ?
In name, yes but not by symbols. N-channel MOSFET pins are SOURCE (source of electrons) - the more negative terminal. And DRAIN (of electrons) - the more positive terminal.

The protocol is reversed for P-Channel MOSFETs by convention (corresponding to the inversion on PNP transistors).
 

MaxHeadRoom

Joined Jul 18, 2013
28,619
I can work in both, but if I have a device that really calls for thinking of electron flow, I find that I will think of electron flow for that device and conventional flow for the rest of the circuit and not find it at all confusing. But if I have to analyze a simple circuit using electron flow I find that I have to be very explicit in what I do to avoid screwing up.
Pretty much sums it up for me also.:cool:
Max.
 

WBahn

Joined Mar 31, 2012
29,979
In name, yes but not by symbols. N-channel MOSFET pins are SOURCE (source of electrons) - the more negative terminal. And DRAIN (of electrons) - the more positive terminal.

The protocol is reversed for P-Channel MOSFETs by convention (corresponding to the inversion on PNP transistors).
The naming is not "reversed by convention", but is quite consistent. The source/drain and emitter/collector refer to majority charge carriers.
 

GopherT

Joined Nov 23, 2012
8,009
The naming is not "reversed by convention", but is quite consistent. The source/drain and emitter/collector refer to majority charge carriers.
I just wanted to be sure the OP did not expect the Source on a P-channel to also be the more negative (source of electrons).
 
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