fluorescent lamp jumps digits in TTL

[chrIsAl]

hello people
i once had a project (which is already finished) that is an adjustable countdown timer which will, if you press the start button, a fluorescent lamp will light and as that time goes out that lamp will be automatically turned off, a buzzer will sound through a pulse generated by a 555 timer..as long as the reset is not pressed, the buzzer will not stop and you cannot readjust the time (at this point the display is 000)....the lamp's supply is a 220V Ac which needs a ballast and a starter to start up, along the connection, i connected a relay for the timer to set up the moments when the lamp has to be turned on or off...
And along the project making, i came across a problem..the timer works perfectly fine if i do not connect the lamp to the relay, leaving the contacts of the relay hanging. but if i do... and i press the start button, the digits just jumps according to the starting process of the lamp...once the lamp has turned on completely, the countdown works again but it is not the time i set because of the jumps that occurred....
can someone explain why does this occur?? and suggest a possible remedy for this?? this project is already finished and i used an alternative, a fluorescent with an electronic starter (the ones that do have to start up) and perfectly worked!.. i'm just curious about this because i still have many things to learn about electronics


THANK YOU!!!

 

[ericgibbs]

hi,
I would say its caused by electrical 'noise' caused by the tube striking.

Do you have noise decoupling on your TTL logic also noise suppression on the tube electrics.??

 

[chrIsAl]

thank you for the reply sir.. can you explain your suggestions further?

if you mean decoupling each TTL IC with a small capacitor, i was only able to do that in the actual PCB..i came across this problem when i was still breadboarding the circuit...i was not able to try if that is the remedy for the fluorescent lamp with starter... sheeeesh... ((

any suggestions for suppressing the noise on the tubes??

Thank you sir...