A little 8 pin DIP that can be hacked into a light or line following robot known as the "Herbie".
The "Herbie" chip!
This very cool little op-amp was designed originally for powering small speakers in portable electronics, but it suitably runs motors too!
Good for up to 15V, dissipating 1.25W maximum, it's got some power. We've measured the input impedance near 50K, and output impedance at about 10 ohms - good enough for driving small motors!