Switch Debouncing

When a switch is thrown, there is often not a sharp transition from ON to OFF (or vice versa), and instead there may be oscillations called switch bounce, Figure 75. Bouncing may last for something like 10 ms, which is a long time for a digital system. These oscillations may cause problems unless handled correctly.

**Figure 75:** Switch bounce.
$\begin{figure} \begin{center} \epsfig{file=images/seqdesimg9.eps}\end{center}\end{figure}$

A debouncing circuit to filter out the switch bounce is shown in Figure 76. Here, R₁ >>R₂, and $R_1C \approx 10$ ms.

**Figure 76:** Switch debouncing circuit.
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