View Single Post
  #36   Report Post  
Posted to sci.electronics.design,sci.electronics,sci.electronics.equipment,sci.electronics.repair
John Fields John Fields is offline
external usenet poster
 
Posts: 2,022
Default Looking for a Low Cost On Delay Timer

On Thu, 5 Sep 2013 12:24:41 -0700, "Guv Bob"
wrote:

"John Fields" wrote in message ...
On Wed, 4 Sep 2013 11:21:01 -0700, "Guv Bob"
wrote:

"dave" wrote in message m...
On 09/04/2013 01:17 AM, Jan Panteltje wrote:
On a sunny day (Tue, 3 Sep 2013 16:01:31 -0700) it happened "Guv Bob"
wrote in
:

Will this work?

Size R & C so that when switch closes, relay energizes after 5 =
seconds, and remains energized until switch is opened.

http://img839.imageshack.us/img839/4650/uh3.gif

Yes, but 5 seconds needs a big C.


http://www.ebay.com/sch/i.html?_odkw...=0&_fr om=R40

Thanks Dave. That's exactly what I have been looking for. Problem is I can only find these or similar units in the $5-20 range from China (2-3 weeks). Omron and others available in US are $70+


---
Why can't you use Jasen Betts' circuit?

--
JF


What circuit is that? I don't see it.


in------+-------------+ | |
| . . . .|. . . . | . VCC(8) .
| . . +-----+-------RES(4) OUT(3)------
out _|_ | . 555 . D1 A [R1]
+---TH(6) DIS(7)-- 'T` | | . .
+-----+---+---TR(2) CV(5)-- | . .
C1 ===== . GND(1) . | . . . .|. . . .
| | ----+-------------+---
ground
U1 LMC555 / 7555
D1 1N914
C1 10uF
R1 470K

--
JF