- Select a time constant based on the bouncing characteristics of your switch
- Select a resistor based on power
consumption, input voltage, or capacitor size limitations
- Power consumption is
calculated with the pullup voltage and resistor value: P =
V2 ÷ R
- Input voltage is
determined by voltage drop across the resistor caused by leakage into
the device input. This is calculated with Ohm's Law: V = I × R
- Capacitor values can be
limited due to package size
Time Constants for Common Resistor and Capacitor Values| Capacitor
(μF) | Time Constant (ms)(1) |
|---|
| R = 10 kΩ | R = 100 kΩ | R = 1 MΩ |
|---|
| 1 | 10 | 100 | 1000 |
| 0.1 | 1 | 10 | 100 |
| 0.01 | 0.1 | 1 | 10 |
(1) Time constant should be approximately half of the desired
debounce time. This is commonly selected as 10 ms to give maximum debounce time
while preventing humans from noticing the delay.