160 IT: Circuit Drawing Using Libre-Office (160.html)

IT: Circuit Drawing Using Libre-Office (160.html)

Introduction
As you can see, these guidelines are being written in early 2021. When creating a Drawing using Libre-Office, I start with a High-Resolution Drawing such as that in Source 1. I use Libre Office because it is free, and because it can generate jpg images of each Drawing. To combine multiple images into a single pdf file, I use Irfanview software. Because most of my Drawings are schematics of electronic circuits, I often include a set of electronic components such as those in Source 2. I don't know how to create a template for LibreOffice Drawings, so I just store my templates as simple Drawings. If I am creating a Drawing to be used in an article, I store my intermediate and final Drawings in that Article's folder.

Gate Maxims
01: A negative output AND gate is equivalent to a negative input OR.
02: A negative output AND gate becomes an Inverter if its inputs are tied together.
03: All unclocked logic can be made from many dual input NAND gates (i.e. negative output 74xx00 AND gates).

Raspberry Pi Electronics Maxims
01: An almost unlimited number of HC gates can be driven by a normal HC gate.
02: HC gates need buffers to drive LEDs.
03: HC gates connected to the outside world should have sockets.
04: Beware of static electricity when handling HC gates.
05: LEDs need a 360 ohm to 1K0 resistor.
06: The Raspberry Pico needs buffers, it can only drive HC and AHC gates.
07: AHC gates can almost always replace HC gates (but tri-state needs more pins).
08: AHC gates at 3v3 are roughly compatible with old TTL gates at 5v0.
09: Opto-Isolators really work.
10: Beware of Triacs with 110v AC.
11: Two diodes in parallel (opposite polarity) drop 0v7 of AC and/or DC.
12: AHC gates are faster than HC gates (and can be Tri-State).
13: ti SN74AHC00N Quad Dual-Input Positive-NAND 14 pin DIP gates from Mouser Qty 1 cost CAD$0.69 tomorrow.
14: CdS (photo resistors / photo cells) need a 6K8 resistor.
15: Supply HC and AHC gates with Vcc = 3v3 .
16: The SN74AHC541N is a great 541 AHC buffer gate.

Recommendations

When starting an electronic schematic, if there is room, I include a copy of the electronic icons in the image below. Then I follow the recommendations below:

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Electronics Elements version A

The image below shows more standard electronic symbols:

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other standard electronic symbols

Begin with a High-Res Empty Drawing (eg Source 01) containing a snap-to grid, such as in Source 1.
Be sure to indicate the final Article where the Drawing will appear.
Save a backup copy of the Drawing every 10 minutes or so.
Rename the Drawing with a different version letter every hour or so.
When moving a group of objects, be sure to include a cross-hairs before & after the move,
keeping the cross-hairs lined up with the grid. [Cross-hairs should be in a corner (e.g.bottom-right)].

Silkscreen Resources

The following symbols are from the Optimum Design Handbook (Source 8 and Source 9) by Optimum Design Associates. See their website in Source 10 .

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