DSO 150 : Avoid 0.6v drop on power supply

There is  a diode (D2)  acting as a reverse polarity protection circuit.
It is very inefficient, we are loosing ~ 0.6 v there.

Better to use a small SMD P-Mosfet transistor instead, such as A1SHB (cost ~ nothing)
Voltage drop is now ~ 50 mV, much better, and we still have the reverse polarity protection


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