How to make a PCB – an ExpressPCB Tutorial (Part 2)

Last night,we’d been through making a Schematic(.sch file) for our PCB layout. You can check that out here.

Lets proceed to making the layout itself. At this point,i am assuming that you have a .sch (Schematic) file ready with you.

1. Fire up ExpressPCB (and not ExpressSCH).
2. Before we move on to the layout,some basics about PCB’s. A pcb can be of different types-single layered,2 layered,4 layered. A layer basically means that traces(copper connections) will be present on the surface. So a single layered pcb has copper traces only on upper surface,a 2 layered pcb has traces on upper and lower surfaces.
3. A single layered pcb is advised for most of the applications,whether you are making a board which has a 40 pin IC or anything else. This is bcoz it is cheaper.
4. However,if you are using RF components of high frequency,then you should probably be using 2 or 4 layered PCB’s .This is becoz there are some issues regarding Power Planes and Ground Planes.
5. ExpressPCB has 2 options-2 layered or 4 layered.
6. This tutorial will deal with making 2 layered PCB’s only.
7. Click —–>File—->New—->2 Layers—->Ok.
8. Then click —-> File—->Link Schematic to PCB—–> (Select your .sch schematic file)—->ok
9. Now remember this…anything in RED is on the upper surface of your board,while anything in GREEN is on the lower surface. Anything in YELLOW means that it is ‘silk’ or just the name or label of a component.
10. Keeping everything in either only RED or only GREEN will make your board single layered. If you have traces in both red and green,it will make your board 2 layered.
11. Rest of the interface is similar to ExpressSCH, only here you have ‘Place Trace’ instead of ‘Place wire’. also there is an additional option of ‘Place Pad’. A ‘pad’ is a hole in your board. It connects the upper layer to lower layer.Components are inserted through holes. Placing pads in your ground and Vcc traces at regular intervals is recommended.
12. Lets proceed with making a layout for the Voltage regulator whose Schematic we made yesterday.
13. Click—-> Component Manager—->Semiconductor-TO 92—->Insert Component into PCB
14. Then place the capacitors. For capacitors, leading space of 4.5mm is sufficient for disc and electrolytic capacitors. For resistors, keep leading space of 0.5 inch. Note that we aren’t using SMD’s over here,just normal components.
15. Now double click on each component. Assign EACH of them the SAME PART ID that was assigned in the schematic(.sch). For eg,we named the capacitors C1 and C2. So give them the same names in the layout. You can see i have done that in the above picture.
16. Click—–>Place a trace—->Then click on one terminal of C1. You will see 2 BLUE marks appearing. One at the C1 terminal and other at the Regulator terminal. BLUE marks indicate that these 2 are to be connected together.
17. Connect all terminals together as per the dots shown.
18. Now to make some of the traces thicker,double click on each one—>Trace type—>Select the Width
19. The main Vcc and Ground Trace should be made thicker than the others. Check out the pic below. Also ,if you want to draw a trace on the lower surface,select the Green icon with arrows pointing downwards. Check pic below. Don’t forget to place ‘Pads’ at regular intervals in the traces.
20. Good. Your nearly done. Re-size the yellow border(outline) of the PCB to make it as small as possible. A SMALLER pcb is a CHEAPER pcb. But take care that its not so small,that you find it difficult to solder components.
21. Congratulations ! Take a print out of the layout,and give it to some professional PCB maker. It’ll be done real cheap. An AVR development board layout that i made myself cost me only Rs. 80 (less than US 2$).

And lastly,today’s Reason To Smile Winner is …..

How to make a PCB – an ExpressPCB Tutorial (Part 1)

Hello !  Not been able to post for a while,coz i’ve been very busy with my minor project and stuff. Today lets see how we can use a software for making custom made PCB’s (printed circuit boards).

i’m going to concentrate on ExpressPCB ,because its easy and free. You can download it from here. After that,install and start it up. Express PCB has 2 main parts – Express SCH which you will use to draw your circuit diagrams ( if you have used Multisim ,this should be pretty easy)  & Express PCB where in you will make your own PCB layout.

Part 1: Making The Schematic

Since it is difficult to make a layout without having a circuit diagram, constructing a circuit diagram in ExpressSCH is strongly recommended. Follow these steps :

1. Fire up ExpressSCH.
2. You will see a ‘Welcome to ExpressPCB …..’ screen. You may go through the quick start guide ,but if you are reading this,that won’t be necessary :-) i’m your turbo start.
3. Click ‘Ok’
4. We’ll first need to place some components.Say we want to make a Voltage Regulator circuit.
5. Lets get familiar with the layout first. Check out the pic below.
   

   The Interface

6. Here is the circuit diagram
   

   Ckt Dig

7. Click on the ‘component and symbol manager’ ie. the button to which i have shown an arrow pointing to in the pic of the interface.
8. You’ll see the above window. Click    Find–>  Then key in ‘lm7805′. Once you find it,select it and click —>Insert into schematic.
9. Again click on ‘Component and symbol manager’ and select the 2 capacitors.
10. Now to connect the components together,click on  ‘Place a wire’ (the option marked in the above pic). Click once on an end of one component,then another time on an end of another component to connect the them together. Use ‘Insert corner in a wire’ option (directly below  ‘Place wire’ ) to bend the wire into a neater right angle. It doesn’t really matter whether you do this or not.
11. Please note than ground,Vcc etc. will be found in —>Component and symbol manager—>Library Symbols.
12. This was all fine because all components you needed were available in the component manager. If that is not the case,then you have to make your own custom component. Pic below specifies the options you can click to do so.
13. Select whatever shape you want .Suppose you want to make a 20 pin IC. So select a rectangle. Then click on ‘Place pin’ option (the 4th of the above marked options).
14. Go on placing 20 dots in a line. Then click on the ‘Add New line’ option (highlighted in the pic below) to complete the 20 pins. Please NOTE : do not use wires to connect the dots to the rectangle.
15. 
16. Next,select ALL the pins and the rectangle using the ‘Select’ arrow (uppermost option on left). Click  —>Component—-> Group to make component—>Ok     from the menu bar on top.
17. Now the most important part. Each component must have a unique Label by which it is referred. To assign this,double click on each component and assign a unique ‘Part ID ‘ to each.
18. Then  click—->File—-> Check component for Netlist errors. If errors are 0,then save the file. If not,then check your schematic as per the error indicated. Mostly it will be some component naming error(2 components having the same label) To resolve that,assign them unique part id as indicated above.
19. If you are using a transistor,you are bound to get this error:-
20. To resolve it,click on the transistor. Then click —->Component—->Ungroup Component. Now click on each ‘dot’ of the 3 legs of the transistor. Assign a number to each (Part ID). Then select the whole component (dots,lines everything making the transistor). Click  —->Component—->Group to make component.
21. Check for Netlist errors again.
22. Finally our schematic that looks like the pic below.  You file will be saved as      name.sch. Very goood ! Lets move on to making the layout tomorrow…Good Night for now ! But before i wind up,the Mover and Shaker of the Day- see the video below