Incandescent Lamp

Okay, okay, an incandescent lamp isn't a motor, so why is this exercise in the motor section? Well mostly because the means of controlling it use much the same parts employed with motors. Besides, a lamp is slightly inductive, don't you know. Anyway, this project really didn't fit anywhere else, so here 'tis.

You'll see in the schematic that there are two options:

In option (a) a beefy Darlington transistor is pressed into service. The lamp I've specified draws three-quarters of an amp at five volts, but Darlingtons are capable of much more. And obviously, this is a DC circuit. If you're really going to go with a 110VAC bulb, then you need to consider some serious safety engineering, things like opto-couplers, relays and so forth.

Option (b) employs a power MOSFET. Be aware that these come in all sorts of flavors. The one I've specified (FQP30N06L) is ideal since it turns on in a digital fashion and is guaranteed to come on fully with the +5V driving its gate.

The exercise simply blinks the bulb under PIC control. Not too exciting, but it does illustrate how to manipulate a current sucking device that would fry a port pin instantly.

Click to get the source code.
Click to get the schematic PDF.

Next Project: Motor Speed Control

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