Hi, I was testing some things on my protoboard to learn a little about transistors. I made this:
The batteries are two AA 1.5V in series. The resistor is a 1Kohm. The transistor in a TIP122.
I uploaded a code that just put Pin9 as OUTPUT and HIGH, so I can test the currents on the circuit.
1.Current beetwen the Pin9 and the Resistor: 1,32mA. 2.Current beetwen the Baterry(+) and the Colector: 0,43A. 3.Current beetwen the Emissor and the Ground: 0,32A.
I can`t understand this currents. I was expecting 3mA ((5-2)/1000) on the 1st case and 3A (1000(gain)*3mA) on the 2nd and 3rd.
Am I doing something wrong? Is this circuit goinbg to damage my Arduino, since there is 0,32A going to the Ground Pin?