I've built my own sound switch, I have it control the lights. The sound activation works great, Attiny85, no problem, But after my IRLZ44N when its in the off position I noticed a -.6 Volts. I hooked it up to the scope and saw a continuous wave form showing up to -9 volts.. I'm new to this, I have some electronic experience, but this one baffled me.. (see attached circuit)..
Thank you
HI,
It looks like you are measuring the Q1 drain with Q1 in the "off" mode and an open circuit.
So basically you are measuring a open circuit with a diode (anode) to ground. You would likely see voltage picked up from the air. It is likely 50 or 60Hz and should not go more than 0.5 to 0.7 v below ground.
What your are seeing is normal, however I cannot explain the -9V. Is the scope on the same ground as the ATTiny?
You could:
Actually one thing that is missing from the circuit is a 10k pull down resistor from the Gate. But I will try your suggestion tonight, I also meant to post screen shots from the scope. But what your saying sounds logical (I had schooling years ago in electronic engineering, was away from it for many years and am relearning it).
Thank you.
You were correct. Everything works great with the load, and it dropped the negative voltage to about .4v
I've attached the screen shot without the load showing -10v
Hi,
Thank-you for a clear and non-fritzy circuit diagram. 
Your layout of the diagram can improve but if its your first try, well done, the fact that you kept the layout open, helps with your wire connections.
The layout can be improved to minimize the wiring, but again thank-you.
OPs original circuit.
Tom...
I'm glad you found the issue.
Good luck.
