Re: on/off circuit

On May 29, 6:15 pm, Rich Webb <bbew...@xxxxxxxxxxxxxxxxxx> wrote:
On Thu, 29 May 2008 05:22:07 -0700 (PDT), steve <kvst...@xxxxxxxxx>
wrote:



I require a circuit that switches off.

It is similar to the pocket calculator that will automatically switch
off if not used in a few minutes.

Could anybody please provide.

You'll need to provide a bit more information. What is being switched?
What's available to sense the "being used" state? What control
signals, if any, are available to control power? Is any warning of
impending power termination required/desired?

The more information you can provide up front, the more targeted the
solutions can be. As it is, there's really no answer to your question.

--
Rich Webb     Norfolk, VA


A led is to be switched off.

A simple circuit is used to switch the led on/off with 9 v.

After the led is first switched on, the switch remains activated/
closed.

However, the led should turn off after a fixed time (even though the
switch remains activated/closed), without being turned on again.
.

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