Missing components in the library...

On Tue, 15 Mar 2011, badbad2142 wrote to us saying :

>Hello,

>Still using the free version and still at newby silly question level.

>I am creating (at least trying to) my first PCB board which is going to

>be a PMW. I started by order all the coponents for m digikey (got an

>head acke with their web tool..)

>My coponents are:

>* SN74ACC14N: Found it sounds good

>* EVU-F3lFL3B14 (potentiometer): even wiht the datacheet I do not find it

Manufacturer part numbers for pots are often of little use. Most

designers are more interested in form factor. That said, the standard

Eagle libraries are short on pots (there's a good selection of presets

but few of the shaft-and-knob types).

>* 1N5817 (diode): can not find it...

Diodes are a classic example of generic parts, where the library

component doesn't match the part number because 57 varieties of diode

all share the same circuit symbol and package. Look in the diode library

under D-fill and select the package that matches the 1N5817 (check sizes

or package names on the data sheet). Then once you've placed it on the

schematic, set its "value" to 1N5817 and you're done.

>* BUL704 (NPN) was not able to find it directly but using the number of

>the datasheet TO-220 whihc was not in the database either I end up

>finding it using TO220...

Again, there are a LOT of TO220 NPN transistors out there, so the

component is generic. There are also specific transistors in the

library, partly because of the potential confusion of pin ordering (so

it's worth checking that the library part you picked matches your data

sheet, although TO220 is much more standardised than, say, TO92)

>* 1N914BTR (diode) was not able to find it...

Again, you can use a generic D-fill and pick the right package. Note

that the 1N914 is practically identical to the 1N4148 too.

>And the list is going and going like that on every conponent.

>My frustration level in rising, I spent more time looking ofr the

>components that I will spend on creating the board (step that I have

>note reached yet...)

>

>So simple question:

>1) I am doing something wrong?

Yes and no. You're expecting exact part numbers where generic

descriptions are used.

>2) If I am not doing something wrong where can I find an extended

>library of components?

Cadsoft web site, in the downloads section.

>3) If netheir one or two is possible, how do you proceed on your side

>to order components? you try to see if they exist in Eagle then in

>DIgikey (for example) and then only order them?

Sometimes I check what Eagle already has and order that, but more often

I either have a specific device in mind or already have a drawer-full.

If none of the Eagle libraries includes the part then I create my own

library part.

If you look back through the archives of this group you will see this

repeated time after time: Learn to create your own library parts! It's

not hard, and you're going to have to do it sooner or later. It will

release the power of the tool and enable you to design what you want,

not what somebody else had left lying around. Don't look on the limits

of the existing libraries as a drawback, look on the ease of adding new

ones as the huge plus that it is.

--

Rob Pearce                       http://www.bdt-home.demon.co.uk

The contents of     | All power corrupts, but we need electricity.

this message are    |

purely my opinion.  |

Don't believe a     |

word.               |

On Tue, 15 Mar 2011, badbad2142 wrote to us saying :

>Hello,

>Still using the free version and still at newby silly question level.

>I am creating (at least trying to) my first PCB board which is going to

>be a PMW. I started by order all the coponents for m digikey (got an

>head acke with their web tool..)

>My coponents are:

>* SN74ACC14N: Found it sounds good

>* EVU-F3lFL3B14 (potentiometer): even wiht the datacheet I do not find it

Manufacturer part numbers for pots are often of little use. Most

designers are more interested in form factor. That said, the standard

Eagle libraries are short on pots (there's a good selection of presets

but few of the shaft-and-knob types).

>* 1N5817 (diode): can not find it...

Diodes are a classic example of generic parts, where the library

component doesn't match the part number because 57 varieties of diode

all share the same circuit symbol and package. Look in the diode library

under D-fill and select the package that matches the 1N5817 (check sizes

or package names on the data sheet). Then once you've placed it on the

schematic, set its "value" to 1N5817 and you're done.

>* BUL704 (NPN) was not able to find it directly but using the number of

>the datasheet TO-220 whihc was not in the database either I end up

>finding it using TO220...

Again, there are a LOT of TO220 NPN transistors out there, so the

component is generic. There are also specific transistors in the

library, partly because of the potential confusion of pin ordering (so

it's worth checking that the library part you picked matches your data

sheet, although TO220 is much more standardised than, say, TO92)

>* 1N914BTR (diode) was not able to find it...

Again, you can use a generic D-fill and pick the right package. Note

that the 1N914 is practically identical to the 1N4148 too.

>And the list is going and going like that on every conponent.

>My frustration level in rising, I spent more time looking ofr the

>components that I will spend on creating the board (step that I have

>note reached yet...)

>

>So simple question:

>1) I am doing something wrong?

Yes and no. You're expecting exact part numbers where generic

descriptions are used.

>2) If I am not doing something wrong where can I find an extended

>library of components?

Cadsoft web site, in the downloads section.

>3) If netheir one or two is possible, how do you proceed on your side

>to order components? you try to see if they exist in Eagle then in

>DIgikey (for example) and then only order them?

Sometimes I check what Eagle already has and order that, but more often

I either have a specific device in mind or already have a drawer-full.

If none of the Eagle libraries includes the part then I create my own

library part.

If you look back through the archives of this group you will see this

repeated time after time: Learn to create your own library parts! It's

not hard, and you're going to have to do it sooner or later. It will

release the power of the tool and enable you to design what you want,

not what somebody else had left lying around. Don't look on the limits

of the existing libraries as a drawback, look on the ease of adding new

ones as the huge plus that it is.

--

Rob Pearce                       http://www.bdt-home.demon.co.uk

The contents of     | All power corrupts, but we need electricity.

this message are    |

purely my opinion.  |

Don't believe a     |

word.               |