Want to utilize that "DC power" jack on your walkman, but it didn't come with a plug?
Need a power supply for that special project but not sure which one to use?
Here's my little guide for picking the best power supply for your needs.
Step 1: AC and DC power
AC power comes from the power company, and is accessible through the outlets in your house.
DC power comes from batteries.
Sometimes we need to convert the AC power from the wall to DC power in order to run a device which normally might run on batteries. The tool for this job is an AC/DC adapter or transformer which is often referred to as a "wallwart" as it sticks out of the wall in an unsightly manner.
Most appliances that require an adapter like this have a label near the power jack which details about the voltage and polarity required.