Simple 555 Timer

[am.steen]

this staircase automatic timer drives me creasy as it is very simple but not working


when power the circuit the Bulb becomes on without press S1 or S2 buttons
what I do
1. removing NE555 from its socket then apply power the bulb is off.
2. replacing the 555 IC and TRIAC but same problem bulb is on.
3. I connect a led and resistor to pin 3 of 555 and power the circuit the led is off then press S1 the led is on for timer period then off ( the Bulb is always on ) this means 555 operation id right.
note
R1 was 10k in original circuit but with this value the 555 triggered from it self ( also with R1=10k the bulb was on ).

What is the problem ??
Or if anyone have a tested staircase timer with TRIAC schematic please send it.

 

[crutschow]

What is a "staircase timer"?
What is the purpose of the 555?
What exactly do you want the circuit to do?

 

[am.steen]

What is a "staircase timer"?
What is the purpose of the 555?
What exactly do you want the circuit to do?

it is a delay timer for stair light when you press a button on the wall the stair bulbs light for a period of time then off automatic
555 is a timer IC
I get the circuit from here

Automatic Staircase Light 1 | Sigmatone

sigmatone.com

 

[crutschow]

when power the circuit the Bulb becomes on without press S1 or S2 buttons

Why is that a problem?
Is the power not applied continuously to the circuit?

Try connecting the positive side of C2 to the V+ supply, and the negative side to pin 6 and R3.
Also change R1 back to 10kΩ.
R3 is not needed--you can connect pins 6 and 7 together.
With that the 555 should power up with a low output.

Be aware that one leg of the 220Vac is connected to the push-buttons.

 

[bertus]

Hello,

I see that the origenal circuit asks for a BT136
You are using a BTA08, wich has a much higher gate current.
Compare the datasheets I attached.

I have also attached a collection on application notes in one PDF for Thyristors and Triacs.

Bertus

 

[Bluejets]

when power the circuit the Bulb becomes on without press S1 or S2 buttons

You power the 555 on it will time out first up and do whatever it is supposed to do.
There are ways around this but not in your diagram.
Check out some details on how 555 timers work.
https://www.talkingelectronics.com/te_interactive_index.html ........... go down the page to 555 timers.

 

[Bluejets]

Be aware that one leg of the 220Vac is connected to the push-buttons.

This is the part that concerns me........... Not a good idea by any means and more likely than not, violates any building code.
Be prepared to face a grilling and other consequences if it ever goes belly up and electrocutes someone.

My advice would be to strongly suggest you forget it and buy a commercial product designed for the job.
..............and get a qualified lecky to fit it as well and save any house insurance queries.

 

[Alec_t]

Your use of a 10k/10W dropper resistor would be a concern for me. It will dissipate nearly 6W and get HOT. It's a fire risk and not eco-friendly. It will cost more to run than the bulb.
Perhaps a mains-rated 6W LED bulb could replace the whole circuit and be left on permanently?