On Jun 29, 7:15=A0pm, steve <kvst...@[EMAIL PROTECTED]
> wrote:
> On Jun 26, 7:56=A0pm, "Tom Biasi" <tombiasi...@[EMAIL PROTECTED]
> wrote:
>
>
>
>
>
> > "steve" <kvst...@[EMAIL PROTECTED]
> wrote in message
>
>
>news:03b46771-e8ad-45bf-8bf9-7fdf483a12cf@[EMAIL PROTECTED]
>
> > Since the 9v battery supply is quickly used up, I am using a ac
> > battery eliminator/wall wart to run the Led timer.
>
> > Although the eliminator provides the needed 12v to 15 v, it also
> > changes the 50 hz dramatically to several khz.
>
> > The khz output from the eliminator completely upsets the 555 timer
> > input, so there is no timing available from with the circuit.
>
> > I tried a 1000uF with several diodes placed at the eliminator=92s
> > output, but there is hardly any production of dc.
>
> > Thanks.
>
> > Steve.
>
> > Sounds like you are using a switching supply.
> > The wall wart is not filtered very well.
> > Also your project didn't address noise on the DC supply.
> > I would suggest non-switching wall wart and clean up the output.
> > I would also look into your design since it wasn't expecting noise
from=
a
> > battery.
>
> > Tom
>
> -----------------------------------------------------------------
> This project was difficult to design, so preferably it should be kept
> same.
>
> I will provide the schematic shortly.
>
> Steve.- Hide quoted text -
>
> - Show quoted text -
-----------------------------------------------------------------
------------------------------------------------ 9 v
| | | |
R1 | | |
1Meg | 555 | R2
| | | 100K
| | |-------------|
| | |---------------------- Out
|--------------|----------- | |
| | |
| | Led or
| 1 uF Buzzer
100uF |
| |
|--------------------|
Unfortunately, Google does not allow image upload here.
This is a 555 timer simple circuit, consisting of:
R1 =3D 1Meg
R2 =3D 100K
C1 =3D 100 uF
C2 =3D 1 uF
The problem is that replacing the led with a musical buzzer quickly
uses up the 9 v battery.
Therefore, I am using a ac battery eliminator/wall wart to run the Led
timer.
Although the eliminator provides the needed 12v to 15 v, it also
changes the 50 hz dramatically to several khz.
The khz output from the eliminator completely upsets the 555 timer
input, so there is no timing available from with the circuit.
I tried a 1000uF with several diodes placed at the eliminator=92s
output, but there is hardly any production of dc.
|
