Power Supplies for the Uninitiated

You’re choosing a power supply for a device, like a retro console. The device has defined requirements, often noted on the device by the plug.

These requirements include: voltage, amperage, the plug’s size (see barrel plugs) AND the “polarity” should be checked in case it’s reversed (rare.)

Electrical Requirements

In short, your power supply must match the Voltage and provide AT LEAST the amount of Amperage.

NES     9V    1.3A
SNES    10V   850mA
Genesis 10V   800mA
Sega CD 9V    1200mA

1000mA = 1A

Polarity

As a convention, the inside of barrel plugs is usually positive. This should be checked before using a replacement power supply. These markings on the device describe polarity. The left is most electronics.

Where I lose you

You’re choosing a Power Regulator (a.k.a. Voltage Regulator) for one or many electronics. These devices’ stated purpose is to provide a consistent and clean voltage.

You can plug it into your SNES and as long as your Power Regulator maintains 10 volts (+/- a bit) your Nintendo will be happy. An undamaged SNES will draw between 0, and 850mA.

You require a 10V power supply of 850mA or higher.

You can plug multiple devices into a power supply, like your PC does, and sum the Amperage requirements. SNES and Genesis coincidently need 10V, so a 10V power supply is required.