Arduino signal generator

[kEhYo77]

Maybe just this.

[madddann]

Well, yes that chip would be perfect for what I need, but I just spent the last 3 hours trying to get it to work with no success.
I have only one chip and that one may be defective. A few times I could see some signal for a fraction of a second when connecting the supply voltage. I could also see the ramp waveform on the capacitor, but other than that there were no other pulsed signals on any other pin.
Did you test your schematic? Was it working for you?
Thanks again kEhYo77, if you happen to think of any alternatives, I'm all ears.

Dann

[kEhYo77]

Yes. I have tested it and it is working for me.

[gyulasun]

Well, yes that chip would be perfect for what I need, but I just spent the last 3 hours trying to get it to work with no success.
I have only one chip and that one may be defective. A few times I could see some signal for a fraction of a second when connecting the supply voltage. I could also see the ramp waveform on the capacitor, but other than that there were no other pulsed signals on any other pin.
Did you test your schematic? Was it working for you?
Thanks again kEhYo77, if you happen to think of any alternatives, I'm all ears.

Dann

Hi,

Sorry to chime in,  this TL494 circuit was a topic on this forum, and member itsu for instance
built the circuit and it also worked for him, see this link with his schematics:
http://overunity.com/12736/kapanadze-cousin-dally-free-energy/msg507286/#msg507286

His circuit is almost the same: the difference is he connected pins 14 to pin 15 and grounded
pin 16,  and he added decoupling capacitors as you can see.
I am not saying the schematic by kEhYo77 is not working, perhaps the trick is the use of the
filter capacitors across the 5V reference and ground and also across the main supply input and ground.
IT would be worth trying these changes.

And here is yet another variant where the dead time can also be varied, besides duty cycle and
frequency:  http://overunity.com/12736/kapanadze-cousin-dally-free-energy/msg502495/#msg502495
Of course your TL494 might be defective.

Gyula

[madddann]

Hello Gyula!

Don't be sorry, any helpful input is well appreciated. I put together the circuit from the schematic by Itsu an it works, but the output signals are kinda jumpy at times, like when I turn the duty cycle pot to a certain value (the pots are new). It's also starnge that when the duty cycle is in the region near max. everything looks good, but when I turn the pot down slowly and evenly, the duty cycle on one output channel (I think pin 9) jumps to minimum and stays there until I turn the pot back up near max. I also played with separate duty and dead time circuit but it's the same story. Tryed two equivalent chips (KA7500B) and still all the same.

The schematic from kEhYo77 works only if I connect pins 1 and 16 to ground.

But maybe I shoudn't rely on cheap chinese protoboards for testing circuits.

Thanks guys!


Dann