Inverters form three phase VCO

synthmonger · Posted: Fri Jul 25, 2008 3:45 pm Post subject:

Oh ya Loss1234 you should make sure you're using cap decoupling. At high end frequencies it sways like a mofo and makes weird chunky noises. After using a .1NF next to the chip and two 100uF against pos and neg rails it went away and was very stable.

I love this, the range is from lfo to hfo with the amplitude staying the same and no noticeable offset.

loss1234 · Posted: Fri Jul 25, 2008 4:28 pm Post subject:

ok i will try that
you are correct i wasnt using ANY decoupling

i will try your expo to fet trick...let me ask, the expo connects to the GATE of the FET? a n channel fet right? and then you connect the source to what? and the drain to pin 1 of the 40106?

thanks

synthmonger · Posted: Fri Jul 25, 2008 4:38 pm Post subject:

Yes, yes, and connect drain to pin 2.

My expo directly to pin one works better though ;p Don't forget the diode, it won;t work w/o it

loss1234 · Posted: Fri Jul 25, 2008 4:54 pm Post subject:

now i am really confused

in your picture, the diode connects pins 1 and 2.
the source connects to pin 1.
the gate connects to the EXPO CONVERTER output.
so where does the drain (of the mpf102)connect? +v? gnd?

thanks

(i assume your schematic refers to the expo to MPF102 you were mentioning before)
also do you still have to use the weird power supply connections??

thanks

synthmonger · Posted: Fri Jul 25, 2008 8:02 pm Post subject:

No in this schematic it's just the output of the expo source connected directly to pin 1, no mpf102 just the one in the inverter schematic. I was talking about another means of controlling the gate with the mpf102

loss1234 · Posted: Sat Jul 26, 2008 6:00 am Post subject:

that clears up everything. so that works with regular power supply rails?

so the what is the diode doing?

these circuits could really open up a new world for me.

thanks

synthmonger · Posted: Sat Jul 26, 2008 6:38 am Post subject:

I don't know, switches the cap on and off maybe? Heh I'm really not sure ;d You can get a semi-sloppy triangle wave from pin 1, at high frequencies it doesn't register and just stays still.

It makes a supppper narrow trigger pulse wave on pin 2 like I said. It really needs to be sent to a wave shaper to get use out of it, right now I'm running it through a frequency divider to get a nice square wave and then sending it through wave shapers.

loss1234 · Posted: Sat Jul 26, 2008 7:15 am Post subject:

can you be more specific about which waveshapers...links, schematics..? i have always wondered what I can DO with a squarewave but have not yet dived into waveshaping schematics as i have never known which ones are useful.

thanks

synthmonger · Posted: Sun Jul 27, 2008 2:02 am Post subject:

I'm just routing a square wave into an integrator and then shaping from there. A pulse wave into an integrator can produce saw/ramp type waveforms and other whacky stuff!

Honestly I would just go from the schematic i supplied then google square to whatever wave form converter and see what comes up.

p.s.
If you use aim my screen name is ihatevideogamez

**edited for clarity

loss1234 · Posted: Sun Jul 27, 2008 3:37 am Post subject:

thanks a lot

i havent ever used instant messaging. but maybe i will try sometime. enjoy your night!!