Hello,
I am using a TIP120 to power up my vacuum motor that runs runs at 3530rpm with a voltage rating at 12V. The transistor's base has 5V input and a 10k resistor. The motor is connected to the collector and a 12V Lead Acid Battery. The emitter is grounded.
From what I know, when initially ON, the amount of current that flows into the motor is about as much as I expected. However, when I disconnected the base, the motor slows down and then the speed climbs and climbs until the TIP120 becomes extremely hot and the motor spins even much wilder. I believe the TIP120 has an internal diode on its own, but why does it not work the way I wanted? Hope someone can give me a pointer. Thanks!
I am using a TIP120 to power up my vacuum motor that runs runs at 3530rpm with a voltage rating at 12V. The transistor's base has 5V input and a 10k resistor. The motor is connected to the collector and a 12V Lead Acid Battery. The emitter is grounded.
From what I know, when initially ON, the amount of current that flows into the motor is about as much as I expected. However, when I disconnected the base, the motor slows down and then the speed climbs and climbs until the TIP120 becomes extremely hot and the motor spins even much wilder. I believe the TIP120 has an internal diode on its own, but why does it not work the way I wanted? Hope someone can give me a pointer. Thanks!