Hz overload

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?s 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

--
Something\'s clearly screwy there.

Why don\'t you post a schematic (not anywhere on USENET, since Google
doesn\'t support binaries) so we can see what you\'re doing?

Or, better yet, download a free copy of LTspice from:

http://www.linear.com/designtools/software/

generate the schematic, and post the text  *.asc file here.

JF

"the 9v battery supply is quickly used up"

Seems like this is the problem, you are drawing to much current from the output of the 555.

I would suspect this is why the 1000uf cap didn't help.

Good Luck,

• * * Christopher

Temecula CA.USA

----------------------------------------------------------------- This project was difficult to design, so preferably it should be kept same.

I will provide the schematic shortly.

Steve.

I will provide the schematic shortly.

Steve.

If its too much trouble for you to fix your design then the only other choice is to supply it with clean DC. Tom

. a

-----------------------------------------------------------------

------------------------------------------------ 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.