Circuit Symbol Sizes and Proportions?

[Chris55000]

Hi!

I'm thinking of an overall review of all my component symbol sizes and proportions used in my SPlan 7.0 drawing software, as I feel the ones supplied as standard are much too large and "clunky" - you can't get much more than a 555 timer circuit on a landscape A4 sheet!

Most manufacturers could draw something like a 6 or 7 valve AM/FM receiver on an A4 landscape template - can anyone suggest:-

1) Suggested dimensions for resistors, capacitors and inductors;

2) Recommended diameter for transistor-envelopes;

3) I want to make thermionic-valves exactly as per Newnes/PW style (rectangle with two half-circles) - can anyone recommend a suitable arc-radius for the semicircles?

The drawing software has a basic grid of 1 mm, and sub-divisions of 0.5 mm, 0.2 mm and 0.1 mm are available. There is both "snap to grid" and "snap to adjacent object" options available.

The A4 drawing space is about 150 mm high by about 250 mm wide, after margins and title-block are deducted!

Ideas and suggestions?

Chris Williams

[mole42uk]

I have used EAGLE for several years and always found it to be much easier than sPlan with a fairly shallow learning curve.

I have just started using kicad which seems to have a more comprehensive library including various valve types with the correct pin allocations. It's free too.

[Oldcodger]

Some folk don't like it, but I've found that Express PCB is worth a look. One advantage is that you can make your own symbols for componants to your own design. e.g. - I've a few 555 layouts depending on how I want the chip to look as. I've never tried a valve , but there is a circle/semi/variations tool.

[Terry_VK5TM]

Is this what you are seeing?

I make it 159mm above the title block and 279 mm wide.

That 555 in the middle is from the standard SPlan library.

[Aerodyne]

Express PCB is my preferred choice - using the .sch section of the program, it is easy to create valve shapes using semicircles and straight lines. The only problem is that line thickness is fixed and there is no choice available.
It is free to download and easy to learn and use. I never use the rat's nesting facility, though.
Tony

[Chris55000]

Hi!

This is my first valve-based diagram using P.W. Newnes-type symbols I designed using my SPlan 7 software!

I've used the Chinese Super-Regen kit as an example to draw it with.

Would Members like to examine and comment on it please? I'd like to know if I've got the symbol sizes, shapes and proportions right for making more complex valved circuits with!

Chris Williams

[Chris55000]

PS!

Since the original thread was published on these kits, apparently the Chinese have worked it out on a PCB!

Note - my drawing should have given 20K for the pot and a 4k7 in series with it as part of the anode circuit!

Chris Williams

[Terry_VK5TM]

Using circuits in PW Jan 1950 as the comparison, your resistors look a little on the small side (and the capacitors maybe a bit large).

The resistor length is approx 2/3rds the height of the valve envelope in PW.

Instead of redrawing the components, you could use the Scale option under the Function menu to adjust the size (click on a component -> Function -> Scale -> set percentage). Then you can measure them and redraw as needed to be correct at 100% size.

Having said that, it seems to depend on who drew the various circuits in PW, as there is a wide variation throughout the magazine, some circuits have the resistor length the same as the valve envelope height.

[Ed_Dinning]

Hi Chris, at first glance the style is very authentic PW/ RSGB.

Now how do I graft it into my EZ-PC or other design suite. With a linking physical model I can then also design valve PCB,s

Ed

[beamcurrent]

Valve circuit. On a quick appreciation, it is very pleasing to the eye, at least my eye.

The symbols are, in a way, like a font choice in writing. Your diagram reads very well for me.

To stick to the writing analogy it's a nice "font" and the grammar (layout) works too.

Brian

[kellys_eye]

Have you made comparisons to those published in magazines?

I'm probably not alone in being able to recognise where a schematic comes from in terms of a publication as they each tend to have specific format/method of drawing. In particular I used to 'like' the way ETI magazine and, more recently, the older editions of Elektor magazine proportioned their drawings (the more recent editions tend to be so complex that scale becomes an issue and magnification is essential).

Personal choice I reckon - there is no defined specification that I know of but simple clarity is basically 'all' that is required.

[Chris55000]

Hi!

I've re-drawn and re-proportioned the resistor and capacitor symbols and made some genuine Newnes "true-earths", - me thinks they're as good as I can get them!

Chris Williams

PS!

I can't promise it'll be a quick job as it will take some time to write but I'll explain how to draught the symbols in due course!

You will require, if you're not using Abacom's SPlan 7.0, EDA/Circuit Schematic Software that can draw on a 0.1 mm/0.2mm grid, or, if your EDA software's schematic editor is scaled in "mils" (thousands of an inch), 5 mil and 10 mils.

I'll deal with the circuit and valve-symbols, then I'll go onto valve-bases!

[kellys_eye]

I think the component values should be in the same font/size as the component designations.

[Chris55000]

Hi!

I think the component values should be in the same font/size as the component designations.

I selected the sizes/fonts using principles suggested in BS530/BS3939, "BBC Drawing Office Practice Guidelines" and generally used by most radio and TV manufacturers of the period covered by this forum - if you examine most maker's drawings (BRC/Thorn, GEC, Murphy are three examples) you will find the component refs are slightly larger than the values!

In fact, the references and values are the same height (3.5 mm) but I have used a "condensed" font for the values - this is done for asthetic reasons as for large values with more than three digits, the value doesn't spread out across a line, and helps with the efficient use of drawing-space!

Chris Williams

[kellys_eye]

I see.

However if you want to 'follow' BSxxx standards you pretty much have your answer! But you mention 'aesthetics' as the reason for condensing the font which, imho, might help with 'long' values but makes me squint on most of them that aren't 'long'!

Perhaps keep the font size the same for designation and value but 'bold' the designation? or maybe try italicising the value?

[Chris55000]

Hi!

As a "PS" it's my aim to produce samples of the British Drawing Office lettering that adorned innumerable Engineering Drawings and Circuit Diagrams from the 1940s to the 1970s, with particular emphasis on the styles & sizes used by Thorn/BRC, (these were made with "Uno" Stencils made by A. West & Partners) but so far every attempt at producing these letters ended up with messy blobs of ink everywhere, even using "Uno" N.O.S. pens/nibs that have never been opened!

The Gill Sans is only a "stop-gap" till I can perfect my "Uno" letters and turn them into TTF fonts for PC use!

Chris Williams

[M0FYA Andy]

For some unknown reason I didn't read this thread in June, but I'm very pleased to see it and have to congratulate you on the results!
I've always been annoyed by the appallingly poor diagrams in the BVWS magazine, with modern resistor rectangles and inductors looking like stacks of pennies!
The old PW diagrams set the standard and you've replicated it.
I've successfully created circuit diagrams in Word, but it's a very slow process.

Andy

[Aerodyne]

I really like the appearance of your diagram. It reads easily and looks excellent. If I was to suggest any adjustment, I'd like to see the valve symbols a little larger whilst keeping the resistors and capacitors as they stand, and the coil symbols perhaps a little smaller.
But this is personal to me - and it's nit-picking. Congratulations on a fine piece of work, a good way better than I can produce.

Tony

[John10b]

For me it is very clear and well proportioned, I like it, I’ve never been a fan of blocks for components etc.
One small observation, the heater line going straight across the earth line to the -supply, would be nice if you could show a “loop” or bridge or what ever you call it. Apart from that I like it.
Cheers
John

[Oldcodger]

John, my practice on my drawings is to break a line and add a loop to the line to cross any non-connected line. The Other method ( which PCB Express does not like) is to make any interconnections on lines as a connection point. ( e.g. a solid small circle).