From: Jim Thompson
Subject: Re: One-Shot
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Date: Sun, 15 Dec 2002 17:45:12 GMT
NNTP-Posting-Date: Sun, 15 Dec 2002 12:45:12 EST
Organization: Cox Communications
On Sun, 15 Dec 2002 17:36:16 +0000,
Terry Pinnell ,
In Newsgroup: sci.electronics.design,
Entitled: "Re: One-Shot",
Wrote the following:
|>Anyone have a circuit for a one-shot that would light up a LED for a exact
|>period of time after a button is pushed, no matter how many times the button
|>is pushed. All the timers I have found are cumulative, and keep resetting
|>the timer every time the button is pushed.
|As John Fields said, a 555 is often used. For example
|would deliver a pulse for about one fifth of a second. Alter Rt and/or
|Ct to get different timings, using the approximation
|t ~ 1.1RtCt.
|Take pin 3 to your LED via a suitable limiting resistor. As mike
|mentioned, you've not specified various key requirements; in
|particular, the voltage supply will determine that resistor's value.
|For example, 12 V with a 1k resistor would give about 10 mA through
|Hobbyist, West Sussex, UK
On the data sheets for *digital* one-shots, observe the application
schematics for *non-retriggerable* one-shots.
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| Jim-T@analog_innovations.com Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
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