Please see images for the setup that I use. The mega is powered from a 7812 and is generating a pwm wave at pin 7 (10us on time and 100us offtime) using delayMicroseconds and toggling the pin. I took the measurements across the 7805 output with the arduino disconnected from 7812. It has a 15mv p-p …

arduino making 7805 output noisy

TomGeorge April 6, 2014, 11:40am 9

Me?
Only 45 years at it that's all.

No Grumpy_Mike..
Doors666 I was referring too.

Tom....