They all have three connections, referred to as the base, the collector, and the emitter (on FET transistors, the three connections are the gate, the drain and the source)
NPN Transistor
- collector go to the voltage
- if we want to control high voltage, better use NPN
PNP Transistor
when the base turn it into the low, it will turn on instead of turn off
- Emitter to the voltage
Darlington and MOSFETs
Snibber Diode can help to prevent the motor, if the circuit is in the wrong way
Lab
Lab: Using a Transistor to Control High Current Loads with an Arduino
- using TIP 120 transistor- The transistor allows you to control a circuit that’s carrying higher current and voltage from the microcontroller. It acts as an electronic switch.
- Add a 1N400x power diode in parallel with the collector and emitter of the transistor, pointing away from ground. The diode protects the transistor from back voltage generated when the motor shuts off, or if the motor is turned in the reverse direction. Used this way, the diode is called a snubber diode.
Lab: DC Motor Control Using an H-Bridge
Motor Driver
code
const int switchPin = 2; // switch input
const int motor1Pin = 3; // Motor driver leg 1 (pin 3, AIN1)
const int motor2Pin = 4; // Motor driver leg 2 (pin 4, AIN2)
const int pwmPin = 9; // Motor driver PWM pin
void setup() {
// set the switch as an input:
pinMode(switchPin, INPUT);
// set all the other pins you're using as outputs:
pinMode(motor1Pin, OUTPUT);
pinMode(motor2Pin, OUTPUT);
pinMode(pwmPin, OUTPUT);
// set PWM enable pin high so that motor can turn on:
digitalWrite(pwmPin, HIGH);
}
void loop() {
// if the switch is high, motor will turn on one direction:
if (digitalRead(switchPin) == HIGH) {
digitalWrite(motor1Pin, LOW); // set leg 1 of the motor driver low
digitalWrite(motor2Pin, HIGH); // set leg 2 of the motor driver high
}
// if the switch is low, motor will turn in the other direction:
else {
digitalWrite(motor1Pin, HIGH); // set leg 1 of the motor driver high
digitalWrite(motor2Pin, LOW); // set leg 2 of the motor driver low
}
}
Lab: Controlling a Stepper Motor With an H-Bridge
- Only uno can use H-bridge IC, L293D
- Nano will only use TB6612 H-bridge (motor driver)
