Re: Diodes for Li coin cell protection

From: Robert Scott (no-one_at_dont-mail-me.com)
Date: 02/05/05 

Date: Sat, 05 Feb 2005 20:41:37 GMT

On 5 Feb 2005 12:11:52 -0800, "rickman" <gnuarm@arius.com> wrote:

>I had to look pretty hard to find a small, inexpensive diode pair to
>allow an RTC to be powered by both a Li coin cell and the power rail.
>The RTC I am using is very low current when not being controlled..

A really low reverse-current diode can be formed by using the
base-emitter junction of a small NPN transistor, like the 2N3904.
Just tie the collector to the base.

-Robert Scott
 Ypsilanti, Michigan
(Reply through this forum, not by direct e-mail to me, as automatic reply address is fake.)