This is the first in a series of Instructables on Powering and Controlling devices. This one shows you how to determine what the voltage and current requirements for your device are. Other Instructables will show you how to select a power source, how to select interface components, and how to connect controllers to your your device.
If you want to buy or build a power supply for your device you’ll need to know the exact voltage and current required by your device. If you want to construct an interface for controlling your device, say from a microcontroller or switch box, than you just need to have a general idea of the voltage and current requirements.
Step 1: Is it AC or DC Powered?
Alternating current (AC) devices are ones you plug into a wall outlet and include things like household light bulbs, appliances, and fans. Some AC powered devices are powered by a transformer that reduces the voltage from the wall outlet to a lower voltage.
Direct current (DC) devices are things that typically run off batteries; small motors, LED’s and panel lights, automotive accessories, portable electronics and most toys. Some DC devices will be powered by an AC-to-DC converter that you plug into the wall - often referred to as Wall Warts.