I'm working on a project that requires a DC motor, so I salvaged a PC fan from an old computer. The model is AVC DS08025R12U. It needs 12 volts for maximum speed and is rated to draw 700 milliamps. I'm planning to power the motor with a 12 volt 3 amp power brick, which will also help power an Arduino microcontroller and a breadboard power supply module. I'm planning on changing the speed of the motor with a PWM signal from the Arduino, but just to test, I set up the simple circuit that can be found on the sparkFun website. Instead of making a simple code, I am just plugging a wire into ground or 5V manually. I also have the Arduino removed from the circuit. Here's a schematic -
Instead of powering the breadboard with the Arduino, I used an Elegoo breadboard power supply module.
I have a wire going straight from the DC jack (12 volts, 3 amps) to the Collector of an S8050 NPN Bipolar Junction Transistor, which, from the datasheet, is able to handle 12 volts and 700 milliamps. Although the power brick does supply 3 amps, the fan is only rated to draw 700 milliamps, which is the maximum amount of amps the BJT can take, after checking with a multimeter, it only draws a little over 500 milliamps, which should be nowhere near too much for that transistor. The datasheet for the S8050 NPN BJT is right here - http://electronics.se-ed.com/magic/s8050.pdf
Is the potential problem in the physical circuit? Am I incorrectly reading the datasheet? Is this normal?
Also, for some reason, when I use 5 volts to turn the transistor on and off, the fan doesn't spin very fast. Only when I plug the jumper cable connected to the base of the BJT to 12 volts does it reach maximum speed, in which case the BJT gets much hotter much faster.
Thanks so much!