[Elecraft] RE Inductors--KX1 #151

[Tom Hammond]

Steve:

At 03:48 PM 1/4/04, you wrote:
>On the KX1 PCB board there are the outlines of the molded inductors on the 
>top and the bottom of board.  My question is ...is there a specific 
>direction that these should be mounted.  I would assume no but why the 
>double-band markings on the PCB board?

They're there just to 'suggest' the orientation to be used when installing 
them.

When assembling components on a PC board, it is generally acceptable 
practice to first decide upon a 'standard' horizontal and vertical 
orientation for all components when they are installed. This allows the 
builder (or whomever) to hold the PC board in one orientation and to be 
able to read all component nomenclatures for horizontally-mounted 
components and then to turn the board (one time only) 90 degrees and to 
read the nomenclatures for the verttically-mounted components.

>Also can someone explain to me the pin numbers for U1 and U3 starting with 
>pin 1 with the dot marking on the chip???

Virtually all ICs are numbered in the following manner:

At one end of the IC, if it is held vertically, Pin "1" will be marked 
EITHER by a small inward-dimpled dot in the upper-left corner OR by a 
square notch in the end of the IC case. Once pin1 has been located, pin 
numbering proceeds DOWN the left side to the bottom, across to the 
bottom-right pin, and back up to the top-right corner.

See the illustration below (best viewed with a FIXED-PITCH font)

     ------          -------
   1|o     |14     1|  | |  |14
   2|      |13     2|       |13
   3|      |12     3|       |12
   4|      |11     4|       |11
   5|      |10     5|       |10
   6|      |9      6|       |9
   7|      |8      7|       |8
     ------          -------

73,

Tom Hammond    N0SS