POWERED DIGITAL OR ANALOG OUTPUT – Again, the simplest output transducer is the LED but for more than the two states available with digital output you need analog output. As before, we can vary the brightness of an LED directly from a microcontroller but to vary the intensity of an incandescent lamp we must amplify the power available from a microcontroller.

Incandescent Lamps: requires more power than LEDs – use transistor

Incandescent Lamp (6-9 volts @ 900 mA) Analog Lamp Driver (same as digital driver) – use TIP120 NPN-D Transistor - Power dissipation of 80W

Inductive loads: Also require more power than LEDs – use transistor and diode

Hobby Motor Motor, Solenoid or Relay (inductive loads) Control Schematic – use TIP120 NPN-D Transistor - Power dissipation of 80W

Pull-type Solenoid Snubber Diode – prevents blow-back voltage caused by inductive loads.

Some recommend putting the snubber across the load as in the relay driver circuit or both across the transistor and the load.