Multisim and Ultiboard
How to set power (watt) to resistor?
Solved!
Let me also answer this question from a pure schematic/design/layout standpoint - as we do get this question quite often:
Power rating is usually specified by the manufacturer and it usually corresponds to the physical size of the resistor (so for a given resistor type and value, a 1/2 watt resistor will typically be physically larger than a 1/4 watt resistor).
For Multisim, most of the basic passive parts are generic (you can type any value, etc...). However if you've found a component that has a certain value, size (power rating) from a specific manufacturer and you'd like to lock the specifications and save it to the database, here is how you'd do it:
First, place the generic passive part in the schematic...
As an example, I found a 1K, 1/4W resistor from Mouser (a 1/4W, 1KOhm from Panasonic, ERJ type with a 1206 footprint package size). So I would place a generic 1K resistor with a 1206 footprint in my schematic such as this and right click and select 'Save component to database...'
Once in the database you can save to the USER or CORPORATE database. Here is the thing - for Passives, we save them to the BASIC group, but you'll want to create a custom family. Since for passives, there is a good chance there will be lots of duplicates for a given subtype (Family), so I would suggest creating a custom family for a specific manufacturer and type... (select 'Add family' button)
So for this component, under Basic, I created a family called "Resistors_Panasonic_ERJ" - which should be specific enough to avoid duplicates - and when I press the Ok button it automatically gets saved as 1kOhm (Ohm symbol).
At this point you can be all done, or, what I would normally do at this point is go back to the component in the Database manager (Tools -> Database -> Database Manager) and locate the part and add some specific information to this part (for my BOM, etc...).
So, here I am - as you can see I usually add information to the part in 2 areas, the 'General' tab and also the 'User fields' tab (as shown). I usually copy and paste from the datasheet and/or vendor to populate these fields quickly.
...
Now when you use the component in the schematic it will now appear as:
Also all the important design information (from a schematic, BOM standpoint) will now be embedded in the schematic and tagged to that component.
Yes - its a little extra work, but worth it when you are trying to organize your BOM or otherwise...
Regards,
Pat Noonan
National Instruments
