Transformation of theoretical circuit in PCB

Note: The text is auto translated from the Greek version

source: Elektor

We will try to manufacture artwork a printed circuit in films using only from the theoretical diagram. The drawing that we will make is simplest after it is constituted by 10 only elements that is to say 4 resistances, two capacitors, two passages of emission of light (led) and two small (transistors NRN of type BC107, or respectively that constitutes a elementary circuit multivibrator that has the possibility of blinking alternately the two led and constitutes a good beginning for that you can also you make your own printed circuit. All this process becomes in the case where does not exist artwork printed circuit and the work should becomes all from the beginning. In case however where you have artwork from magazine, or following process it is unnecessary after you can remove artwork in films with a simple photographing.

 

 

The materials that you will need for the manufacture artwork are:

1.      Auto transferable (Letra-set) with lines 1 -2 mm thickness and islands (pads) diameter 2,5 -3 mm 

2.      Paper with subdivisions per 1/10 of inch,

3.      Transparent paper (rise paper) or transparency.

4.      Felt-tip  of indelible ink with thin nose

5.      Pencil, rule, rubber  etc

The above materials are required for the production of artwork printed circuit without the use of computer with which we will deal later. Basic rules for the designing: The drawing should be clean, explicit and readable. The placement of materials in their final place will be supposed to have point of report the main elements, where round them will be placed secondary. It is good you follow also at the placement the same process without however this is absolute.

 

 

Prefer make separate line of tendency of catering that would be found in the above part of printed circuit. The line of common point of report of that is to say ground good is it is double at least thickness from the other and it occupies the down part pcb.

If in the circuit exist other distinguishable points, as entry, exit, points of control etc you can him place in utmost pcb easier connection. Prefer the shorter street for the union of two points. This is the straight line. When the corridor (track) changes direction you prefer it becomes or with curve or with bent of 45 degrees.

These are certain from the more basic rules of designing that concern the right output of theorist and following them it aesthetically can men pcb your constitute work of art, but technically will be right and when him you assemble you it will reward working with first without problems.

 

BEGINNING THE DESIGNING

In the theoretical diagram of form 1, you see multi vibrator with two transistors that undertakes it blinks successively two passages of emission of light acquaintances more as led.

Manufacturing him you might him use in systems of warning, alarm, games etc Initially you take a photocopy of theorist and you place on her one transparent paper (rise paper). With help of pencil you draw the elements as they are actually, above their corresponding drawings. When you finish it will be supposed the quadrant of diagrams of materials it resembles with that of form 2. You remove transparent rise paper and place above the paper with the subdivisions in tenths of inch, as it appears clean in form 3. 

You will wonder why in tenths of inch and no our acquaintance from the High school "millimeter paper'". The answer is simple. All the distances between the pins elements, are in entire submultiples of inch. This became when were placed the industrial specifications (standards), for the industry of manufacture of printed circuits. This specifications follow all the designers because the automatic instruments of treatment pcb (drills, cuttingly, machines of assembly etc) are manufactured with them precisely the specifications.

Of course if you you want to make yours pcb nothing you it compels him to follow, but because the work becomes better if it becomes from the beginning rightly, you prefer follow the specifications in order that the problems that you will meet later are less and smaller.

Then you are placed in all the points where exists pins element, but also connection of elements (node) a island (pad). Consequently you will need so much pads those who they are elements on 2, after have two pins each one and moreover two still after transistors they have three pins. Globally you will place 24 pads, as it appears in form 3. You begin to link the islands between them where exists connection with corridors (tracks) thickness of 1 mm

For example with the felt-tip or with auto transferable (Letraset) you link the point of C transistor TR1 with utmost resistance R1 and in point (+) electrolytic capacitor C1. Then you link but utmost the R1 with cathode led. Flowingly you pull a straight line line where you will connect the D1, R2, R3 and D2. this line constitute also the line of catering of circuit, With fussy continue linking the points that are connected between them always consulted the theoretical diagram of form 1.

After you finish with all the connections you make the connection of ground with thicker corridor (2 mms). If you want you can with the help of auto transferable letters place also various clues as Vcc. GND. or even your name, so that it is impressed in pcb. Know you "MHTSOS ELECTRONICS". Your drawing now has the form of form 4. When you remove the transparency, the circuit that you will have drawn it will resemble with the circuit of form 5 and it constitutes the finally drawing of printed circuit. Attention when him you print him you do not place in reverse above in photosensitive pcb. Then, if you see carvings or imperfections you can him correct with felt-tip . Artwork that you will help you make first you printed circuit is ready.

Look after and you we will say that from this you might make one of real pcb printed circuit  reading the corresponding article.

 

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