Many pieces of portable battery powered equipment such as radios, tape recorders cassette players, personal stereos, calculators and electronics games offer the ability to be powered from MAINS power.

There are four things you need to know to replace your AC/DC Adaptor:

1) Output Voltage and milli-Amps
2) Output Polarity
3) Regulated (Switching) or Un-Regulated (non-switching) Output
4) Output plug size

1) Output Voltage and milli-Amps

Usually the volts and milli-Amps (mA) are printed on the original adaptor, and often also on the device that uses the adaptor.

Choose a voltage equal or lower than required
Choose milli-Amps equal or higher than required

2) Output Polarity

This applies only to adaptors that convert AC to DC. The AC to DC adaptors will have a negative centre or a positive centre. To determine the polarity of your adaptor look for a symbol like this: