driving a TIP120 from an output pin of an MSP430

A small circuit set up with a snap circuit kit to test whether the TIP120 can be triggered by the output of an MSP430 low power microcontroller. Even though the TIP120 requires 5V at the base to switch it on, it seems the 3.6 V from the MSP430 pin is enough to do the trick as well... it remains to be seen whether it will still work when the MSP430 is being run off a battery and not the usb port though...


The MSP430 is programmed to turn on the output of pin 5 briefly and then off again, which activates a TIP120 transistor which allows current to flow through the DC motor which spins the toy fan.

Category:

Howto & Style

Tags:

• TIP120
• MSP430
• snap circuits experiment

[MJAndersonPhoto]

Clarification. Per the data sheet, the Emitter-Base Voltage spec of 5 volts does not mean it "needs" 5v it means that above that it will burn out.

[xy9izzy]

@MJAndersonPhoto

oic ok thx

[MJAndersonPhoto]

hope that helps!

[MJAndersonPhoto]

Instead the TIP120, like other bipolar transistors. are current amplifiers - put a little current in and they will switch much larger values. As the TIP120 is a Darlington (actually TWO transistors inside the case) its gain is much higher than a single transistor. For the TIP120 the gain is 1000 so if you put in 1 milliamp it can pass 1 full amp through the collector-emitter circuit to drive that motor.