1 minute timer circuit

[ertiexd125]

can anyone give me a timer circuit using 555 which is working. i found some circuit in the net but some people says its not working. The timer will start as soon as it receives an input on pin 2 of 555 let's say a led on pin 3 will light but when it reaches the specific time let's say 1-10 minutes it will turn off.

 

[DerStrom8]

Here's a basic circuit for what you want to do:



To determine the amount of on-time, you simply use the equation T=1.1RC.
So, if you decide on a specific amount of time, put that in for T and pick a value for R or C. From there, you can find out the value of the last component you need. You could also use a variable resistor for R.
Hope this helps!
Der Strom

 

[MikeMl]

What is your supply voltage?

 

[ertiexd125]

Sir Strom the circuit you have given me will really help but i have few questions. By the way i want to use an LDR for the trigger meaning if there is no light there will be an input to the trigger.

Will the led that will be connected to pin 3 will be on as soon as it will be triggered and wait for lets say 1 minute to be off? or the timer will start for 1 minute then the led will be On?

Sory for noob questions, i'm just a begginner on this!

 

[DerStrom8]

The "noob questions" are just fine--even the greatest electrical engineers began by asking "noob questions"

In order for an LDR to trigger a 555 timer, I would recommend using a comparator circuit so that it "knows" when to send a trigger pulse. If you use the following circuit, it should turn ON the output of the 555 when the LDR senses dark:



R2 is the LDR. The potentiometer is used to adjust sensitivity, and you'll see that R6 and C2 are labeled R and C. These correspond to R and C on the other schematic. The whole thing can be powered from a nine-volt battery, though other voltages could be used. Also, the supply pins are not shown on the LM393 comparator, so be sure to connect pin 4 to (-) and pin 8 to (+).
I hope this helps!
Der Strom

 

[ertiexd125]

Yes sir , I will use a comparator. Sir the idea will be like this when the LDR sense darkness and the darkness will remain for a long time. The Led should On and will remain on until the preferred time and it will not turn on unless the LDR will sense light and then dark again. Will it work like that or what? i'll hear your answer soon sir..

 

[ertiexd125]

sir? w8ng for ur reply^^

 

[DerStrom8]

sir? w8ng for ur reply^^

Apologies. I've been rather busy.
In the circuit I previously posted, the output of the comparator will be on as long as the LDR senses dark. Therefore, pin 2 of the 555, if I am correct, will continue to trigger the output. In other words, the output of the 555 will stay on until the LDR senses light. I'm not quite sure how you could get the circuit to do what you want.
Can anyone else jump in here?