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which is the best and most efficient way to generate saw tooth waveform? I mean by:
i- 555 timer
ii- 8038 ic
iii- Micro controller
or any other?
i- 555 timer
ii- 8038 ic
iii- Micro controller
or any other?
Saw tooth wave form generation
- Thread starter Hamza Khan 4
- Start date
Welcome to AAC!
You need to be more specific. Best and efficient in what way? Minimal components, cheapest, easiest to source, prettiest, easiest to build, lowest power consumption ......?
What amplitude, frequency, accuracy, stability .......?
Here's a simple one :-
You need to be more specific. Best and efficient in what way? Minimal components, cheapest, easiest to source, prettiest, easiest to build, lowest power consumption ......?
What amplitude, frequency, accuracy, stability .......?
Here's a simple one :-
The 555 will do it, but the threshold points are 1/3 and 2/3 of Vcc. You'll probably need amplification and level shifting.
Not sure about the 8038, I know it will do triangle wave. The 8038 is long obsolete along with the MAX038 that superseded it.
The comparator triangle generator can be rigged for a fast rise or fall time, but hard work in demanding applications.
Unijunctions and programmable unijunctions were an old favourite, and some designers still use the discrete component equivalent as the old devices get harder to find.
Some of those options can be made more linear by using a constant current source instead of a resistor to charge the timing capacitor - you need decent Vcc for the CC to work at all, and the linearity improvement is greater if you feed the CC with a higher voltage.
Hello,
The 555 may need a constant current source also depending on your definition of a sawtooth.
The 8038 does not need that, but it's obsolete so i find it hard to recommend this. I hated to see these parts becomes obsolete.
A microcontroller can not directly generate a sawtooth, but again it partly depends on your requirements. IF it has a DAC and IF you dont need too high of a frequency you can do that too. There are also tricks you can use if you have multiple i/o ports available.
Because the spec's are so important to the choice of components, you should probably define your sawtooth a little better.
For example, do you need 0 to 1kHz, 0 to 100kHz, 0 to 1MHz, 0 to 100Mhz, etc., and is the max voltage 1v, 5v, 10v, etc., and is your supply voltage 3.3v, 5v, 12v, 15v, etc.?
Also, how accurate does the sawtooth have to be relative to it's shape? Sometimes a curved sawtooth is acceptable and that is easier to generate for example.
How much are you willing to spend for parts?
All these things play a part in the selection of the 'best' method'
The 555 may need a constant current source also depending on your definition of a sawtooth.
The 8038 does not need that, but it's obsolete so i find it hard to recommend this. I hated to see these parts becomes obsolete.
A microcontroller can not directly generate a sawtooth, but again it partly depends on your requirements. IF it has a DAC and IF you dont need too high of a frequency you can do that too. There are also tricks you can use if you have multiple i/o ports available.
Because the spec's are so important to the choice of components, you should probably define your sawtooth a little better.
For example, do you need 0 to 1kHz, 0 to 100kHz, 0 to 1MHz, 0 to 100Mhz, etc., and is the max voltage 1v, 5v, 10v, etc., and is your supply voltage 3.3v, 5v, 12v, 15v, etc.?
Also, how accurate does the sawtooth have to be relative to it's shape? Sometimes a curved sawtooth is acceptable and that is easier to generate for example.
How much are you willing to spend for parts?
All these things play a part in the selection of the 'best' method'
Last edited:
Last time I checked they are still available on ebay.
Those I bought a year ago work just like they should however they don't look like NOS(real cheap too) so most likely someone is copying the chip using the Intersil name...
Hi,
Yeah i wonder where they are coming from. Maybe extreme overstock.
I made a typo in my last post too, i meant to say that i find it hard to recommend the 8038 because it is obsolete. But if you can find one and you are happy with it then all is well.
One model is still available as "current" on Digikey. At an extreme price.
https://www.digikey.com/product-det...uctor-corp/CMPP6028-TR/CMPP6028-CT-ND/5324497
These (crystal oscillators) are nice, maybe even 'best' by criteria other than cost.
Are you looking for a variable frequency saw-tooth waveform generator or do you need a single, fixed frequency?
Disregard my crystal oscillator answer.Hi,
Wow what a price. Nice to see them still around though.
I only used one in my career. Only saw maybe three in use elsewhere.
I bought a box full of stuff from a closing TV repair shop. There were three in a carefully marked envelope in that box. I have them in my junk box but never found a use for them.
Hi,
Yeah ha ha, and i was always sort of afraid to use them in a new design because i had viewed them as esoteric and almost a novelty rather than a steadfast part that i could be sure could always be obtained. That and the fact that i dont think their specs were as good as i would have wanted anyway compared to some other design doing the same thing. If it is hard to ensure something will work over a certain range of changes i dont like to use it unless it is the only possible way to do it.
I've really only seen them used in designs for intro Electronics books (they show up in nearly every one from the 1970s to mid-2000). Also Forest MIMS workbooks.
