Re: "universal" power symbol

I can imagine a schematic sheet with so many of them it would look like a thunderstorm.

What's wrong with a net name and an optional comment on the schematic?

There are international standards for schematic symbols and reference designators, which are often abused. CON4, JMP6, TR7, DIO12, IC3.

Comment in plain English.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

I would have thought a connector that could be either a source or sink of power would be a rare occurrence.

If you just mean something to indicate that two wires are connected together (regardless of what power actually flows - and which way) a simple dot serves in most cases. If I need to indoicate a specific type of terminal, which could be demountable, I use a circle with a diagonal line through it (like a reclining Greek letter phi), which used to mean a screw terminal in the days when wireless sets were built on ebonite panels.

My office is full of them.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

It falls down on the "bury it in the details" concept, but:

Solid line over dashed line for DC input. Sinewave (or sinewave-in-circle) for AC input. If an input can accept both, use both symbols.

Combine the solid-over-dashed or sinewave symbol with the generic input /output symbol: circle with an arrow pointing into the circle for input, circle with an arrow pointing out of the circle for output.

That's not too bad for things like cell phones and other devices that charge via USB - the lightning bolt is pretty well understood to mean "charging". The icon for "charging in progress" is pretty universally a lightning bolt over a battery icon.

"Shock hazard" gets three lightning bolts and the !-in-triangle symbol. :) Maybe the "book with letter I" symbol if you want them to go read the manual (protip: nobody ever reads the manual).

Circle with arrow pointing in, circle with arrow pointing out.

It might be good to additionally label it with the expected input or output range, but maybe that's too much detail. Like, "0-5V" for an analog input, or "24 V (sinewave)" for an AC output, or whatever.

Matt Roberds

Plain English is always best IMHO. For power I'd use "POWER" or "MAINS" and if not enough space "PWR". Same for field which could be abbreviated "FLD". Aircraft cockpits are a good example, they do not have any of those nonsensical "pictograms".

I had a Europeanized Chrysler when I was young. One day a yellow light below the dash lit up. Looked like a sideways Big Mac and I couldn't find it in the manual. Called the dealer, no clue. Went to their repair shop, lots of headscratching. After some searching through microfiche instructions (no Internet back then) it turned out to be the warning signal for insufficient material left on a brake pad.

When that happens on a US car it says "BRAKE" and everyone knows.

In message <10cll53$2vfai$ snipped-for-privacy@dont-email.me, Don Y snipped-for-privacy@foo.invalid writes

Is that "Power" as opposed to small signals and data ?

How about a "battery" symbol ? lightning bold usually implies a hazardous voltage . There is no symbol for a hazardous current.

Closest I can find

In your application it might not be hazardous . You don't want to instil fear and alarm.

Brian

Just messing around a bit, but "V" is universally accepted as a symbol for voltage, so I wondered about this:

It suggests volts in/out but without the shock hazard association of a lightning bolt. I guess there's room to add a ~ above the V if you wanted to make clear it's AC.

For DC I just use a battery symbol. For AC I use an oscillator symbol. Both with the details in English.

Cheers

Phil Hobbs

I don't mind putting a note on the schematic RIBBON CABLE TO ENCODER BOARD or things like that.

I don't release schematics with chatty notes about the layout.

All of our schematics do start with a block diagram and a table of contents by sheet.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

a lot of USB ....

In that case the symbol doesn't need to convey the literal meaning of "Power", it just needs to convey "That cable goes here". A letter or a number would do equally well, but if you must have a symbol it could be a simple geometrical shape that you haven't used anywhere else.

No you don't. As long as the cable plugs into the hole with the same symbol as the plug, it will work. It won't matter to the user if that is an Ehernet connection, a power connector or an optical SPDIF output. No need to read anything or understand why you are doing it.

When the user can't get it to work and calls in someone who realises there is no power on the machine, that is the time for the expert (or the user who has exhausted all the wrong possibilities) to read the manual and try to understand the system.

If you really want a symbol for "Power input" how about the split circle with a line, which is the "On" symbol on power switches?

The same. The difference between a switch and a connector should be obvious to the user - the mental connection between them would be less obvious but could be established by using the same symbol for both.

The split circle with a line is actually the standby symbol. The power symbol is a full circle with a line in it. John

All this arguing about pictograms is abundant proof that pictograms don't work. My car has lots. For most, without the manual, impossible to guess what they mean.

Jeroen Belleman

Here is an interesting strategy for asking technical questions.

1. Put half, or less, of the requirements in the first post.
2. When people make suggestions, explain why none of them will work.
3. Perhaps include some additional requirements (e.g., physically small devices) when explaining why the suggestions won't work.
4. When people make further suggestions, explain why none of those suggestions will work either.
5. ???

1. Profit!

I wish you luck.

Matt Roberds

Are you new here? That's been the standard process forever.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

If the item has a DC input (barrel jack or USB-C) then I think the 'plug' symbol still conveys the idea of 'power supply' - people know that you need a wallwart to interface between the wall socket and the barrel jack.

Theo

Yes, a plug in profile (side or top) looks similar whichever country you're from. Maybe it has three pins not three but that doesn't change very much. A UK plug viewed from the side has two pins, because L is directly behind N or vice versa, but three pins if viewed from the top.

Pins and cord. The exact shape of the pins or the housing isn't so important.

Theo