Continue to Site

# Need HELP in long delay 555 Timer

Status
Not open for further replies.

#### vincentspm

##### New Member
Hi,

I'm gonig to design a timer with about 5.5 hour OFF and 13 sec ON.

TRIED:
1)i had try is using 555 timer and (3 x 4017) counter
2)5 hour = 5*3600 = 18000s
3)Setting Astable 555 timer, R1 and R2 = 100k and C=0.0001F,
get 0.05Hz clock, 13s ON, 7s OFF
4)cascaded 3 x 4017 counter,connect to output pin 11,
cycle time(20) multiply 1000(3 x 4017 counter) = 20000s = 5.5Hour

PROBLEM FACE:
The high output from 3rd 4017 counter will base on 2nd 4017 clock,
there 2000s ON and 18000s OFF.

Any one can give me a help on this, i need to ON in less than 1 minute??

You need an off time of 5.5 hours and an on time of 1 minute (or less). That is a ratio of 330. Make a counter that divides by 400 and has an off time of 5.5 hours and an on time of just under1 minute. Clock with a pulse every minute.
I hope you know that if you take one of the outputs of a 4017 and connect it to the Reset pin then the part will count up to that count and reset.
Look at TI.COM data sheet. There is an example using three 4017s and 2 AND gates. You get a divide by 1000. By using the reset pin you can make a divide by 400 with a 1/400 output.

How to get a 1/60hz clock. Use a 4060 to divide by 16384. It has a built in oscillator that can be set to 273hz.

Thank you 1st, i will go try it

anyone can help me....i'm using AC to DC adapter(9v) for supplying my circuit, all the counter crazy already....why??
use 9v battery no problem, but 9v battery not enough to drive the motor.

hi need a help about a real time clock ,i have a led i want to turn it on at 6:00am and turn it off at 12:00am...

Status
Not open for further replies.

Replies
14
Views
3K
Replies
43
Views
10K
Replies
34
Views
1K
Replies
5
Views
3K
Replies
1
Views
2K