Circuit 03 – Transistors and Motors

The Arduino will allow you to attach low power devices directly to its pins but items such as motors requiring more power require a transistor. A Transistor allows you to switch big volts using little volts. In circuit 03 we wil be switching a motor.

It uses a 1N4001 diode to act as a flyback diode which eliminates or suppresses voltage spikes seen across an inductive load when a voltage supply is suddenly reduced or removed.

Transistor Data

The transistor here is a NPN (P2N2222AG) type which means that:

  • Connect the load(motor) to the collector
  • Connect the emitter to the ground
  • Connect the base to the Ardiuno pin – when a small current flows along this pin it will allow voltage to flow between the collector and ground and activate the motor.

Transistor Data Sheet

  • Max Voltage = 40v
  • Max Current = 600mA (milliamp)

Motor On and Off again

Simples this one….

Motor on and off again with speeds

This one uses analog values to set the speed of the motor.  I’ve added a little loop at the top which stops the motor from going on and on in respond to nothing forthcoming when I was looking up how to stop the Arduino loop.  It was also interesting to see that the motor doesn’t really respond under ~50.

Finally with Acceleration

This was the final one I tried and it works ok.

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