Re: Minimum switch current

On Wed, 01 Aug 2007 11:49:42 +0100, Eeyore
<rabbitsfriendsandrelations@xxxxxxxxxxx> wrote:



Robert Scott wrote:

I noticed that some switches are specified for a minimum current as well as a
maximum current. Someone once told me that this is because that minimum current
is needed to "burn away" oxides where the metals contact. Well, this is a
problem for me because I am designing a low-power device that will run on a coin
cell battery. The switch that I want to use is specified for 1 ma. minimum
current. But I want to use the internal microcontroller pull-up for this user
input switch. Are there some types of switches that have no minimum current?
How much trouble can I expect if I just ignore the spec? What about putting a
01 uF cap around the switch to produce a short burst of high current when the
switch is closed?

A capacitor is probably the worst idea ever.

What you're describing is usually called 'dry switching'.

---
Whether that's what it's usually called or not, it's wrong. Read my
reply to Sloman's post in this thread.


--
JF
.

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