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triangular waveform generator

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munx8

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hi..i'm want to build the function generator that

produce triangular wave using the concept of charging and discharging the capacitor and not using any IC's

can anyone show me how to design the shcematic for it ?
plz help.. thanxs
 

First use a current source with I1 to charge a capacitor.
Second a current controlled sink with two times I1.
Third both conected to the same side of the capacitor, the other side to ground.
The current source always active, and charging the capacitor.
When the voltage in the capacitor reaches the level that you want or need, then activate the current sink and the capacitor will discharge with I1.
When the voltage in the capacitor reaches the low level that you need then desactivate the current sink.
To activate and desactivate the current sink you need a schmitt trigger, that you can implement with transistors.

This is a relaxation oscillator, we already simulated and implemented and worked very well.
 

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    munx8

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Recall the basic trigonometric calculus of d(sinx)/dx = cosx.

sinx is the fundamental component in square wave.
cosx is the fundamental component in triangular wave.

To achieve this, pump a square wave into the input of a differentiator (using an op-amp, see https://www.allaboutcircuits.com/vol_3/chpt_8/11.html for the circuit diagram). The output is a triangular wave.
 

Miguel Gaspar said:
First use a current source with I1 to charge a capacitor.
Second a current controlled sink with two times I1.
Third both conected to the same side of the capacitor, the other side to ground.
The current source always active, and charging the capacitor.
When the voltage in the capacitor reaches the level that you want or need, then activate the current sink and the capacitor will discharge with I1.
When the voltage in the capacitor reaches the low level that you need then desactivate the current sink.
To activate and desactivate the current sink you need a schmitt trigger, that you can implement with transistors.
This is a relaxation oscillator, we already simulated and implemented and worked very well.
Click to expand...
Can you please supply me with further details?
I'm simulating it, but it gives a dc value at the output at low freq (few KHz) , i.e. the triangular wave is continuously increasing till it dies, while at relatively high frequencies (100's of KHz till MHz) is with no DC .
Also, another problem, it's amplitude is small. (few mV), and since i'm making a funct. gen., i need a wide band amplifier.
Please aid me
 

A simple way . Charging/discharging a cap with a constant current source gives a linear rise/fall.this could be used to get a triangular wave.


Simple .

Step 1 : Generate a square wave.(astable multivibrator or any multivibrator)

Step 2 : Convert that sq.wave to current(v to i ) and charge/ discharge the cap.
your (recipe)triangular wave is ready..a simple opamp is great to use for this.

555 can also be used but I fell this is simple and no need to know the pin details.



see the attach.
 

what if i want to design the circuit without using 555n or 566?
 

This is an astable circuit that generates a triangular signal over the capacitor (diferential output). You can modify the Vdd, Vss or the resitance values to modify the output's amplitude abd the signal's frequency.
If you don't like working with BJTs you could also interchange them with MOS (obviously you would have to recalculate everything).

I hope this helps,

diemilio
 


well i dont think its quite difficult to design a square wave generator once u designed this square wave generator, u just make integrator circuit that gives u triangle wave ........as output
 

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