| 232298 |
2004-05-02 03:43:00 |
Not very critical. I wouldn't go much less than 4k7 (4.7 kilohm) or more than 47k (47 kilohm ... which would be reasonable assuming the logic is CMOS). It's a pullup which holds the line at "5V" except when the switch is pushed, when it becomes "0V". These are quite acceptable as logic levels. ;-)
10k is a nice round value. The reason for the resistor is that it's a Bad Idea to short a power supply to ground. It might give a logic low level, but there are other problems. |
Graham L (2) |