Looking for simple 555 relay circuit

[Soeren]

Hi Fred,

U2A-B state is indeterminate when S1 is open

Err, nope. That's taken care of by the resistor from pin 4 to pin 1/2.


--
Regards,
Soeren

* If it puzzles you dear... Reverse engineer *
New forum: <URL:http://www.ElektronikTeknolog.dk/cgi-bin/SPEED/>

 

[Terry Pinnell]

Soeren <Look@iNO-SPAMt.dk> wrote:

Hi Terry,


As I said, "Breadboarded and works fine." Would you like to see a
screenshot of its output? And it simulated OK too. There's always the
possibility that I've drawn a different circuit to the one I simulated
and built, but at a quick check that doesn't appear to be the case.

Obviously *too* quick!

Yup

I guess you are one of the build-first-make-drawings-later kind of guys ?

Well, I hope your designs are beter than your guesswork, then! You
haven't been around these groups long, it seems, or you'd probably
have guessed better.

I guess you're one of these guess-now-find-the-rationale-later kind of
guys?

Like most of my designs, this was drawn first (and simulated) and
*then* successfully breadboarded. But the initial schematic didn't
include the lamp and relay, just the logic. Not sure what ECAD program
you use, but CircuitMaker, like several others I know of, doesn't
require an explicit Vdd line for hybrid circuits like that one.

On later preparing the finished schematic I thought I'd better add
some token caps to the supply line, and carelessly hung them on that
convenient horizontal line as you saw. It was then easy to take my
buzzer to the same node too! In mitigation, my wife was calling me
down to dinner at that time...<g>

Even if you are, build after the schematic when it is finished, or better,
let somebody else build it up, it will catch all these drawn-late-in-the-
night errors

Just a tad patronising? But, even if I felt I needed such reassurance
for a simple circuit like this, I don't normally have a 'somebody
else' permanently on hand with the requisite skills. Do you?

Does your circuit actually work, BTW?

Fred's post prompted a closer look and I've now
corrected that silly drawing error. Any more problems with this
working circuit?

Not except that you cannot adjust the timing and you have to use a buzzer
instead of a cheaper "loose" piezo disk

OK, but timing was covered by my footnote. And Zhanglu never answered
my specific question about the type of 'beeper'. Unless he enlightens
us now, we'll never know if my assumption that it's a DC-powered
device was correct.

(Just teasing you know

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[ZhangLu]

Yes, thank U so much.

ZhangLu
Malaysia


"Terry Pinnell" <terrypinDELETE@THESEdial.pipex.com> wrote in message
news:4ngcb0holjciq0c98ddprebe399kd922b3@4ax.com...

"ZhangLu" <hechong@pc.jaring.my> wrote:

Thanks everybody!! I've learned a lot from all of you.

BTW Terry, may I assume that this circuit works on 12V DC and the
+ve input is around C3?

Yes, it works fine at 12V. I assume you have the corrected schematic?
http://www.terrypin.dial.pipex.com/Images/LightBeeper-ZhangLu.gif

Pins 14 and 7 of the 4011 (or 4093) go to 12V an 0V respectively.


I intend to use a heavy duty relay to replace Q1 MOSFET to drive the 55W
lamp.

OK. Instead of wiring to the gate of MOSFET Q1, use a simple relay
driving section like that in Soeren's circuit.

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[Soeren]

Hi Terry,

Well, I hope your designs are beter than your guesswork, then! You
haven't been around these groups long, it seems, or you'd probably
have guessed better.

On and off for several years, but my guess was only based on two drawing
errors I have seen recently from your hand (and simple circuits like those
_is_ easy to build from the top of your head

I guess you're one of these guess-now-find-the-rationale-later kind of
guys?

Nope not really.

Like most of my designs, this was drawn first (and simulated) and
*then* successfully breadboarded. But the initial schematic didn't
include the lamp and relay, just the logic. Not sure what ECAD program
you use, but CircuitMaker, like several others I know of, doesn't
require an explicit Vdd line for hybrid circuits like that one.

OK.

On later preparing the finished schematic I thought I'd better add
some token caps to the supply line, and carelessly hung them on that
convenient horizontal line as you saw. It was then easy to take my
buzzer to the same node too! In mitigation, my wife was calling me
down to dinner at that time...<g

Yes, it can easily go wrong, especially right before dinner

Just a tad patronising?

Just trying to be helpful, sorry if it sounded otherwise

But, even if I felt I needed such reassurance
for a simple circuit like this, I don't normally have a 'somebody
else' permanently on hand with the requisite skills. Do you?

Not on my premises, but I either test build _or_ scrutinize the drawing
when it is ment for a newbie to follow, since they are the ones who might
get scared away from a great hobby if things go wrong.

Does your circuit actually work, BTW?

Of course ;D

OK, but timing was covered by my footnote. And Zhanglu never answered
my specific question about the type of 'beeper'. Unless he enlightens
us now, we'll never know if my assumption that it's a DC-powered
device was correct.

Agreed... And don't get me wrong, I did not mean to put you down, I would
never have responded this way if I thought you were without talents


--
Regards,
Soeren

* If it puzzles you dear... Reverse engineer *
New forum: <URL:http://www.ElektronikTeknolog.dk/cgi-bin/SPEED/>