Bus capacitance
Also: line capacitance
The total capacitance seen by a shared signal line.
Device inputs, traces, cables, and probes add capacitance; with a pull-up it produces a finite rise time that constrains data rate.
- Units
- farad, commonly pF
- Formula
τ = R_pullup C_bus
Example 10 kΩ and 100 pF give a 1 µs time constant.
Common misconception A digital edge is not instantaneous merely because its logical state is binary.