8 Threads found on edaboard.com: 555 Delay Circuits
Circuit as shown in pictures:
Design concept: U0 (not shown) is the output of the door before. After delay 0.5 seconds of NE555, the 3 feet of 74LS74 form rising edge and the 5 feet (U1) output high level, through triode connecting relay (not show
Analog Circuit Design :: 07-18-2016 02:02 :: Kimmy10 :: Replies: 1 :: Views: 167
Hi guys. I'm new here so a little back'ground. I'm an automotive mechanic with a background in automotive electronics. that being said I'm working on a project and while I do work on automotive components this goes a little deeper than I ever need to go. I need a component that I can momentarily trigger to energize a relay for 5 seconds. I hav
Elementary Electronic Questions :: 10-30-2012 00:06 :: newb12 :: Replies: 7 :: Views: 583
From what you describe you need two stages of timers.
1: delay after initial sound begins (or ends?)
2: 'on' time for activating equipment
It may be easiest to use a second 555 IC. There's the 556 which contains two 555 in one package.
Otherwise if you are willing to experiment, you can use a simple RC combination and find the (...)
Hobby Circuits and Small Projects Problems :: 01-31-2012 18:12 :: BradtheRad :: Replies: 4 :: Views: 3136
You could use a 555 timer i.c. in the monostable mode.
The output would switch a relay with more than one set of contacts. One set, in parallel with the button contacts, would close and maintain the power until the end of the 3 second pulse - at which time the whole thing is automatically switched off.
The other set of of contacts is fre
Analog Circuit Design :: 05-14-2011 09:23 :: Syncopator :: Replies: 7 :: Views: 9211
Check for "555-circuits" or 555 timer/555 monostabil multivibrators & even general: triggered timer circuits...., we have such at EdaBoard too...
Simplest solution is for you: per switch loaded serial RC element of 1uF & ca2.7MOhm to basis of a transistor, their Collector/Emitter has your relay...
Elementary Electronic Questions :: 01-17-2010 06:53 :: karesz :: Replies: 3 :: Views: 3049
You may want to describe the intended circuit operation more clearly. To my opinion it's hard to understand either from the circuits or your description.
Generally, introducing a delay in the said range involves capacitors of about 1000 uF. It can be implemented more easily with active parts, either timer circuits with (...)
Hobby Circuits and Small Projects Problems :: 04-25-2009 07:32 :: FvM :: Replies: 6 :: Views: 3398
Single capacitors quite often don't work well as delay circuits ..
Maybe you should consider the very popular 555 timer .. something similar to this:
Hobby Circuits and Small Projects Problems :: 08-13-2006 00:55 :: IanP :: Replies: 8 :: Views: 3944
You don't have to worry about triggering a 555 from a CMOS-level logic source as long as you use a CMOS 555 variant, which in fact is a must if you want such long delays: 1-hour.
With standard 250 nA BIAS input currents you won't be able to acquire 1 hour delay without special (...)
Hobby Circuits and Small Projects Problems :: 10-07-2003 01:01 :: silvio :: Replies: 3 :: Views: 1914