I want to control a 5V valve from my BeagleBone Black.
As a single GPIO port only has 3.3V with 8mA I cannot use common relays.
I found this thread:
how to use a 3v output to control a 5v relay
which covers the same issue. However I do not understand the result.
Does a single N-Mosfet enough to let this work or do I need all components shown in the circuit?
How do I calculate the values and type of the resistors, diode and N-MOSFET in that type of circuit?
Best Answer
A single MosFet can do what you want, provided you use an appropriate MOSFET.
Because your GPIO can only output 3.3 volts, you need to carefully choose your MOSFET. Look at mosfet gate characteristics for gate threshold voltage. The FQP30N06L mosfet has gate threshold voltage of 1.0 to 2.5 volts, and your 3.3 volt system can easily supply this minimum threshold voltage.
The link you provide does show additional resistors. Without further information from you, just go with the typical resistors shown.