so which you reommend i input to.Yes. Swapping the inputs will invert the PWM output.
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so which you reommend i input to.Yes. Swapping the inputs will invert the PWM output.
a question aside
1)in sinusoidal PWM does it matter which pin the sine wave is fed into?
some ppl feed the sine wave to the inverting input and the triangle wave to the noninverting input,while some do the opposite.
Does it matter?
2)Can the TL082 opamp generate triangle waves up to 30Khz comfortably.
it seems to be the only opamp available and common here where i stay
Hello,Hi again,
Well you would feed the sine (or signal) into the non inverting terminal to get a genuine PWM output at the output of the comparator itself, but if you need to use a driver after that then you have to consider if the driver inverts or not. If the driver inverts, then you'd want to feed it into the inverting terminal most likely. If not using a driver then depending on what you will use it for will require feeding it into the appropriate pin. But for a regular PWM out of the comparator itself the sine (or the signal) goes into the non inverting terminal.
I think we found the minimum slew rate for the TL082 to be 5v/us, so if we assume a plus and minus 10v output that means for a triangle centered at 0v we have 2us up, 2us down, 2us down again, 2us up, for a total time period of 8us. The inverse of 8e-6 is 125000, so that means the theoretical max frequency of a triangle (not a sine) would be 125kHz, assuming the forced gain of the circuit isnt too exceptionally high.
I would keep it less than that however, and i would think that 30kHz would be ok. If we go too high on the frequency with a triangle then we have to start thinking about some harmonics and the gain bandwidth product. For example, the 9th harmonic of 30kHz is 270kHz, so with a gain of 10 we start to get close to the limit for that sinusoidal frequency, so maybe a gain of 10 would be a limit point we might want to use for a 30kHz triangle in order to maintain a good triangular waveshape.
since an LC filter is used what type of capacitor is used then in the LC filter.A polarized capacitor can be used on DC but not on AC.
You do not connect a capacitor directly to the output of the transformer because at high frequencies it is a short circuit. Usually an LC filter is used.
what type of capacitor does one recommend when filtering the output of an inverter.
i noticed that non polarized is often used when placing at the output of the inverter transformer to do the filtering but can one use a polarised capacitor at the AC output and if not so why?
Hello,compliments of the season to you.The datasheet for the TL082 shows a graph of its voltage gain vs frequency. Its high frequencies have less gain so that it does not oscillate when it has 100% negative feedback (a gain of 1).
The datasheet also has a graph that shows its maximum output swing vs frequency (its slew rate).
With an output of 10V peak its output shows distortion and some attenuation at 150kHz.
A triangle waveform has straight sides when its harmonics are not attenuated below 10 times its frequency.
So a TL08x opamp produces a fair (but not good) 20kHz triangle waveform but a funny-looking one at 30kHz.
Hello,compliments of the season to you.
From what you said does that mean that if I decided to use a TL084 instead of TL082 it could not give a good triangle even at 40Khz-50Khz.
I read a note online where TL084 was used to generate triangle waves at 50Khz.
If you use a 13.5V battery then the output Mosfets will swing to about 13.2V. Then if you use a 15V transformer the 13.2V swing is too low by 15V/13.2V= almost 14%. Then the 220V output will be 194VAC.Hello,
In inverters, will using a transformer that is rated higher than the power supply voltage affect the quality of automatic stable voltage regulation under various loads.
if i use a 12V power supply and i use a 15-0-15/22ov transformer will the auto regulation be as effective as using a transformer that matches the power supply voltage like 12-0-12/220v or lesser than supply voltage 10-0-10/220v?