MOSFET and cap->pot question

[s.r.v.]

Hi,
I have two questions, both for my screamer build!

First of all, how do you use MOSFET's as clipping diodes in a circuit? its a premade pcb so i dont have 3 holes for the leads! 

My next question is is there a way to wire up capacitors to a pot so the capacitance changes? I know pots do resistance, but I have some big ideas....

Thanks!

[Sir H C]

To use a MOSFET as a clipping device you can either tie the drain to the gate, this is called a diode-connected transistor.  The only problem is that when the device is reversed, the body diode conducts and so if you run two anti-parallel, you might not hear the MOSFET clipping, only the body diodes.

For the second question, no, it is tricky to do a variable capacitor.

[s.r.v.]

i think i understand. is it like this diagram?:
http://www.beavisaudio.com/Projects/FKR/images/MightierMouse.gif
so id solder drain/gate together and they would go in the negative spot while source goes in the positive solder pad?

i guess ill do a rotary switch for caps

[Sir H C]

Yes, that is how, the diodes keep the MOSFETs from not working right. 

Yes, the caps is best by switches, what do you wish to do with the caps, sometimes you can do certain functions with a resistor and a cap.