I am trying to turn on/off a few 5v relays with my Wemos D1 Mini. The Mini uses 3.3v so I am trying to use a transistor connected to the relays. I am using an MPS A92 (PNP) transistor.
My question is this:
When I use a multimeter to test the voltage of the Base, when nothing is connected to it, I get a reading of 4.48v. Is this voltage suppose to be there? Also, is the voltage dangerous to my 3.3v mini?
Here is a diagram and an image of my setup:
With a 3.3v mini, use a NPN, wire as Q1 is wired.
Do not forget the base resistor!
An Arduino 3.3v output cannot turn off the PNP transistor if the load power supply is 5v.
“Also, is the voltage dangerous to my 3.3v mini? ”
It could burn up your Arduino!
Always use a base resistor!
I am using an MPS A92 (PNP) transistor.
Wrong sort use a NPN. You will never be able to turn off a PNP transistor because your output from the Arduino does not go high enough.
When I use a multimeter to test the voltage of the Base, when nothing is connected to it, I get a reading of 4.48v.
That is a silly and totally fruitless thing to do.
Is this voltage suppose to be there? Also, is the voltage dangerous to my 3.3v mini?
Yes and yes
