Completed Project pulse waveform and square waveform

Thread Starter

drakedog2

Joined Sep 24, 2014
17
Hi, I try to generate 3 waveform including pulse, square, and f/2 square. The attachment is draft schematic. The DC power I use is 5v-10v. should I use opamp or LM555. I am wondering if there is a better way to generate the waveform. Thanks
 

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MrChips

Joined Oct 2, 2009
24,445
If you want to generate digital signals stay with digital components.
Generally speaking, one expects a square wave to be of 50% duty cycle. Hence you can use a 555-timer circuit to generate pulses at adjustable widths but use twice the desired frequency. Then divide by two to generate the square wave.
 

Thread Starter

drakedog2

Joined Sep 24, 2014
17
T
If you want to generate digital signals stay with digital components.
Generally speaking, one expects a square wave to be of 50% duty cycle. Hence you can use a 555-timer circuit to generate pulses at adjustable widths but use twice the desired frequency. Then divide by two to generate the square wave.
Thanks for the response. Here is the waveform I want to generate. The duty cycle of pulse cannot be twice of the square wave that is why I used two timer. I try to figure out how to use one timer to generate 3 waves or different way to generate the waves.
 

KeithWalker

Joined Jul 10, 2017
1,942
The simplest circuit I know of uses a LM555 timer chip. The potentiometer varies the mark/space ratio of the pulses.Varying the value of R1 will change the pulse frequency.

Variable M_S.jpg
 

MrChips

Joined Oct 2, 2009
24,445
Use one 555-timer to generate a signal at twice the frequency. Use one D-type flip-flop to get the square wave.
Use a second 555-timer in monostable mode or a CD4538 monostable multivibrator to generate the pulse.
 

dcbingaman

Joined Jun 30, 2021
469
Hi, I try to generate 3 waveform including pulse, square, and f/2 square. The attachment is draft schematic. The DC power I use is 5v-10v. should I use opamp or LM555. I am wondering if there is a better way to generate the waveform. Thanks
How accurate does the frequency need to be? The 555 is fine if you don't need high accuracy. Most Cap's are not highly accurate. So if no accuracy, a 555 followed by two flip flops gives you what you want. If not, you need a crystal oscillator on the front end and slightly different design.
 
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Thread Starter

drakedog2

Joined Sep 24, 2014
17
I tested the circuit. It works fine but if I use two 555 timers to generate the strobe and D0 waves, they aren't synchronized. now I try to convert the D0, square wave, to strobe, pulse. Is it possible to turn a 0 to 5v square wave into 0 to 5v pulse using just passive components?
 

dcbingaman

Joined Jun 30, 2021
469
I tested the circuit. It works fine but if I use two 555 timers to generate the strobe and D0 waves, they aren't synchronized. now I try to convert the D0, square wave, to strobe, pulse. Is it possible to turn a 0 to 5v square wave into 0 to 5v pulse using just passive components?
Use one 555 to generate the pulse waveform. Send the output of the pulse waveform to a JK flip flop clock input, this will generate the first synchronized square wave. Send the Q output of the first JK flip flop to the clock of a second JK flip flop. The will generate the second 1/2f signal synchronized to the other one. If using JK just tie J and K high for toggle ability. If using DQ you will need to tie the /Q output to the input to get the toggle effect.
 

sparky 1

Joined Nov 3, 2018
591
The LM567 datasheet shows quadrature square wave and the divide by 2 in figures 14 and 16.
5V 12mA typical operation, .01Hz - 500kHz
https://www.ti.com/lit/ds/symlink/lm567c.pdf
There is alot examples of simple digital applications are available online.
Easy to put together on solderless breadboard,
The internal voltage controlled oscillator and the phase lock make it useful for locking onto frequencies.
http://electronic-projects.50webs.com/phase-locked-loop--pll--oscillator.htm
You can compare to an op amp
http://electronic-projects.50webs.com/op-amp-square-wave-generator.htm
 
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Thread Starter

drakedog2

Joined Sep 24, 2014
17
Thanks for help! I will use 555 to generate the square wave DD and use monostable to generate the pulse signal. use flip flop to generate the freq divider converting the DD to D0 .
 
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