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An Arduino pin can only push a few milliamps. That is plenty for an LED, but a motor wants far more current than a pin can ever supply. ⚡

Even a small DC motor can pull hundreds of milliamps when starting. Connect it straight to a pin and you risk frying your board instantly.

A driver is a middleman. Your pin sends a tiny control signal, and the driver switches a much bigger current from a separate power supply.

The simplest driver is a single transistor. A small voltage on its base lets a large current flow through, like a faucet your pin gently opens.

The motor draws from its own supply, not the Arduino's 5V. The pin only flips the transistor, so the heavy current never touches your board.

The motor supply and the Arduino must share one ground. Without a common reference, the transistor never sees a clean on or off signal.

To your sketch, a transistor driver looks just like an LED. You set a pin HIGH to run the motor and LOW to stop it.

For heavier current a logic-level MOSFET is the go-to switch. It wastes little energy as heat and handles motors a small transistor cannot.

You rarely wire transistors by hand. A driver module packs the switching parts onto one tidy board you simply plug into.

A single transistor can turn a motor on and off, but it spins only one way. To reverse a motor you need more, which the next lesson covers. 🔄

The whole point of a driver is isolation: it lets a fragile 5V pin command a powerful load without ever risking the Arduino itself.

Why can't you connect a DC motor directly to an Arduino output pin?

Pins are weak, motors are hungry, so a driver like a transistor or MOSFET switches a separate supply. Share ground and you protect your board. 🚀