For my circuit the primary Power Supply is a 6V Solar Panel (Note that for the most part the Solar Panel is usually well below 6V but it varies anywhere between 6V to 0V depending on light conditions.)
However there will be times when I want to power the circuit using a simple 5V USB Adapter.
Here are the design requirements:
1) I will NEVER remove the Solar Panel from the circuit. 2) I want the Solar Panel to automatically disconnect from the circuit when the 5V USB Adapter is connected to the circuit. 3) I'd prefer not to use any IC's or things of that nature. I wanted to accomplish this using MOSFETs (preferred), diodes if necessary, resistors, and capacitors/inductors if necessary.
I've seen similar posts to this and they've been moderately helpful but I haven't found anything that has helped me with a fully functioning circuit as I've described in the requirements.