# Same Input and Output but delayed by certain milliseconds.

#### patelyash302

Joined Jul 26, 2021
10
I am new to electronics world and I would like to design a time delay circuit using the 555 timer. The input to the circuit is a square wave with certain frequency and the output should be the same square wave but I need it to be the delayed by 3 to 6 ms. I have also attached the 555 datasheet here in case you need to take a look at it. Additionally, I am open to use any other chip as long as it is accurate in the time delay. Thank you

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#### MrChips

Joined Oct 2, 2009
30,436
I am new to electronics world and I would like to design a time delay circuit using the 555 timer. The input to the circuit is a square wave with certain frequency and the output should be the same square wave but I need it to be the delayed by 3 to 6 ms. I have also attached the 555 datasheet here in case you need to take a look at it. Additionally, I am open to use any other chip as long as it is accurate in the time delay. Thank you
A square wave would be assumed to be a continuous wave with no interruptions.
What is the frequency of the square wave?

#### patelyash302

Joined Jul 26, 2021
10
A square wave would be assumed to be a continuous wave with no interruptions.
What is the frequency of the square wave?
the frequency is about the 20hz

#### MrChips

Joined Oct 2, 2009
30,436
Off the top of my head I would derive a CLOCK signal off both rising and falling transitions (maybe using an XOR gate) and create delay using monostable multivibrator. From here there are various ways to regenerate the square wave.

74LS86 XOR gate -> 74LS123 monostable -> 74LS74 D-type flip-flop

(or using 4000 series CMOS logic gates)

If the signal frequency is fixed at 20Hz you can do it with two 555-timer ICs or one 74LS123 or CD4538 IC.

#### ericgibbs

Joined Jan 29, 2010
18,625
same square wave but I need it to be the delayed by 3 to 6 ms.
hi 302,
What is the total start finish of this 20Hz sqr wave string , how long a duration is the string.?

E

#### ericgibbs

Joined Jan 29, 2010
18,625
hi 302,
This is one option, uses a 555 timer, variable Astable for the clock.
E

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#### MrChips

Joined Oct 2, 2009
30,436
3-6ms variable monostable followed by fixed 25ms mono stable.

#### patelyash302

Joined Jul 26, 2021
10
hi 302,
This is one option, uses a 555 timer, variable Astable for the clock.
E
It seems like that you used the shift registers, 555 timer and some gate logic to solve the problem, However, I do not understand how does the 555 timer is connected in the schematic?

#### ericgibbs

Joined Jan 29, 2010
18,625
hi,
The V2 source is the actual 555 output.

Do you follow.?
E

A quick show.

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#### patelyash302

Joined Jul 26, 2021
10
hi,
The V2 source is the actual 555 output.

Do you follow.?
E

A quick show.
Yes it is making sense now. So, just to restate the circuit in my words, the 555 timer will generate the pulses and that will be feed to the register, and the 8 bit coming out of the register is our shifted output right?

#### ericgibbs

Joined Jan 29, 2010
18,625
hi,
Yes, from the AND gate output.
The Clock rate from the 555 will vary the delay time, using a Pot.
I assume your project is running 5V logic levels.??

E

#### patelyash302

Joined Jul 26, 2021
10
hi,
Yes, from the AND gate output.
The Clock rate from the 555 will vary the delay time, using a Pot.
I assume your project is running 5V logic levels.??

E
The project is to adding a time delay into the analog signal which is more or like a square pulses as shown in attached file and then convert it to the sine wave with time shift and manage the amplitude. I have attached the images to give you some more idea on it. Thanks for your efforts.

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#### ericgibbs

Joined Jan 29, 2010
18,625
hi.
You did say.
input to the circuit is a square wave with certain frequency and the output should be the same square wave

This input waveform swings +/-3v and it is a pulsed analogue signal, with 0V gap and discontinuous.!

E

#### MrChips

Joined Oct 2, 2009
30,436
A bipolar discontinuous signal is a different matter altogether that calls for a different solution.

1) Use an analog bucket brigade.

2) Use an ADC, MCU and DAC.

#### djsfantasi

Joined Apr 11, 2010
9,151
The required circuit is available in an integrated circuit. Search on distributors for “delay line”. One such IC from digikey is an LTC6994HS6

UPDATE: This chip is used in commercial guitar delay pedals. It is built for audio with no conversion to square wave and back. Hence, better sound.

#### Ian0

Joined Aug 7, 2020
9,440
This answers the original question.
The output squarewave is inverted. If a true version was required, use a 74LVC1G17, or invert the output again.

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#### patelyash302

Joined Jul 26, 2021
10
hi,
The V2 source is the actual 555 output.

Do you follow.?
E

A quick show.
So do you think I can follow the same process with my square looking pulse which is continuous and pass it through the shift register? the output of the registers will be the digital right? and if that is a digital then I can use DAC to convert it back to the analog. After that I can use RC circuit to change it to the sine wave what I am looking for. Please let me know if this is the correct process to move with. I appreciate your help.

#### patelyash302

Joined Jul 26, 2021
10
I am working on a project which required me to make a circuit using the passive elements to add a time delay of 5 to 6 ms to to the input analog signal. The input signal has a frequency of 20 HZ and it look like a one positive square pulse for 200 micro seconds than goes zero for 100 micro seconds and then negative pulse for 200 micro seconds, for rest of the period signal is zero.

I tried implementing the RC and RL circuit but it gives phase shift of about the 1 ms. Additionally, I cannot use the coax cables as I am looking for small circuit. any other suggestion will also be welcome.

The main purpose id to add delay and convert it to the sine wave, but for now I am mostly concerned about adding the delay as I can make it sine using the RC circuits.

The image gives a good idea that how is the input look like and the required output.

Thanks

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#### AnalogKid

Joined Aug 1, 2013
10,943
The input pulses package is 500 us wide, but the output pulse package is 8 ms wide? No passive circuit can make that change happen.

Please rotate and re-post the image.

ak

#### patelyash302

Joined Jul 26, 2021
10
The input pulses package is 500 us wide, but the output pulse package is 8 ms wide? No passive circuit can make that change happen.

Please rotate and re-post the image.

ak
here is the rotated image. Do you think it can be done using the digital circuit? also, if we do not consider the pulse width, can we still add time delay using passive elements? any suggestions will be helpful. Thanks

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