Timer With On-Off Delay

timer with on off delay circuit using ne 555 project

555 Timer With On Off Delay Circuit

Here is a timer circuit using common IC 555. The circuit is designed to facilitate time adjustment of both charged and discharged states of the relay.

timer with on off delay circuit using ne 555

R1 1KΩ
R2 470Ω
C1 100µf 25V
C2 0.01µf
D1 IN4001
D2 IN4001
Q1 SL 100
IC1 NE 555
RL1 12V 400Ω

The circuit uses IC 555 in astable operation. Separate delays for charged and discharged states of the relay are achieved by using two diodes (D1 and D2) and two potentiometers VR1 and VR2 provide control over the ‘on’ and ‘off’ stages of the relay, respectively.

The circuit with given values of VR1, VR2 and C1 provides time periods that are adjustable between a fraction of a second to about one-and-a-half minute approximately.

IC 555 used should be in good condition (preferably a new piece); old ICs can sometimes give wrong results. And capacitor C1 should be of a good make, such as ‘Keltron’ ,’Uptron’ , ‘philips’.

Please send your ideas, which are very important for our success…

Tags: , ,
19 comments on “Timer With On-Off Delay
  1. Prem says:

    Can we use 12v instead of 15?

  2. syed.s says:

    this circuit i will operate 24 volt relay,what can i do?

  3. Bhupendra Singh Rathore says:

    I made the timer circuit but the relay is not operating as the coil voltage is low it’s 2.8 volts. Please suggest what can I do to rectify it.

    • admin says:

      check transistor and please use diode (like 1N4001) parallel with the relay. (Diode cathode to positive side , flyback diode – for protection)

  4. kiran reddy says:

    this circuit works perfectly.

  5. sujatna Lokananta says:

    I need the delay off timer after the power on.
    It means that whenever the power source connected, the relay is automatic energize within certain period and then back to dis energize.

    So delay off timer is just work one time only when after the power source is connected to the circuit.

    please your advise me the circuit diagram.

    Thank you for your assistance.

  6. Mark says:

    I stumbled on this while looking for a timer that does exactly what this one does.

    Is there somewhere I could get a PCB to populate for this project, or the completed timer itself… or do I just have to “breadboard” it and put it all into some kind of case?

    Thanks for posting the instructions!

  7. khalid says:

    i need 1 to 20 sec
    so value of variable resistor

  8. Eng M oarafa says:

    For 220 Vac without use transformer Pls what’s the modefecations

  9. ahmed says:

    sir i need one timer first on time is 30 minutes then after 30 minutes turn off for 45 minutes it means 30 min on and 45 min off any body help me

  10. Navya says:

    I need on period of 5sec and off period of 15 sec

  11. Peter O says:

    Relays are not charged or discharged, they are simply on or off with the normal position defined.
    And why on earth have you chosen to use a 15 VDC supply, they are not exactly commonly available. Surely 9 or 12 VDC would suffice?
    Finally it’s not clear to me whether the on & off times are linked, in other words does adjusting one alter the other?

  12. Bilguun Batsuuri says:

    hi sir. I want to make timer which I can control the how long should be on? can you give this type of schmematic of the timer? / sorry about my English, I am not a native speaker/

  13. Heshan says:

    Dear sir,
    I have to change it about 2minits- 5minits. can you please tell me how it wants to change.
    Thak you,
    Best Regard,

  14. Dave Harnett says:

    I need an On delay of about 3 seconds, and an instant off. Will switching the supply power ON give the delay required, and then switching power OFF, should give an instant off?
    Is this correct?


  15. ILIAS ANISIS says:

    MORE THAN PERFECT!!!!!!!!!!!!!!!!!!!
    VR1 100 K ( RESISTORS)
    VR2 3 M ( >> )
    12 Volt
    To energise a pump of hot water from my sun collector to my tank plus a thermostat. Your circuit and directions were simple and fast to construct. THANKS A LOT

Leave a Reply

Your email address will not be published. Required fields are marked *


This site uses Akismet to reduce spam. Learn how your comment data is processed.

Electronic Circuits


Enter your email address: