Why does a DC motor need a diode?
Diodes only allow electricity to flow in one direction (the direction of their arrow). When you turn the power off to a motor, you get a negative spike of voltage, that can damage your Arduino or the transistor. The diode protects against this, by shorting out any such reverse current from the motor.
Does a transistor control voltage?
The transistor allows you to control a circuit that’s carrying higher current and voltage from the a lower voltage and current. It acts as an electronic switch. The one you’re using for this lab is an NPN-type transistor called a TIP120. The datasheet for it can be found here.
What happens if you don’t have a diode in a transistor?
Without the diode, the voltage across the motor would get as large as necessary to keep the current flowing, which would probably require frying the transistor.
Why do you need a fly back diode on a DC motor?
Adding a diode in parallel with the motor provides a path for dissipation of stored energy when the switch is opened +5V The flyback diode allowscharge to dissipatewithout arcing acrossthe switch, or withoutflowing back to groundthrough the +5V voltagesupply. Pulse-width modulation (PWM)for DC motor speed control
When does the diode conduct what happens to the voltage?
The changing field produces a “back EMF” or voltage going the wrong way. The energy goes out the pipe it came in. (Hope I have that right. I’ll check and edit if I have it backwards.) The diode will conduct if the potential, or voltage, across the motor winding is more than about 0.6V in the “wrong” direction.
What is the purpose of the diode in an Arduino?
2 Answers 2. The diode is to provide a safe path for the inductive kickback of the motor. If you try to switch off the current in a inductor suddenly, it will make whatever voltage is necessary to keep the current flowing in the short term. Put another way, the current thru a inductor can never change instantaneously.