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…

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10 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

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