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

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:
   
   
   
   This symbol shows a positive centre. The - and + signs would be reversed for a negative centre. NEVER choose an adaptor with the wrong polarity as this can damage the equipment.
   
   AC to AC adaptors do not have any polarity and so will not have a polarity symbol.
   
   
3. Regulated (Switching) or Un-Regulated (non-switching) Output:
   
   Most AC adaptors are un-regulated, meaning that they do not have any way to cause the output voltage to remain constant. Most electronic equipment have internal circuitry to deal with this.
   
   Some electronic equipment such as digital cameras or security cameras are very sensitive to the input voltage and so require a Regulated (otherwise known as switching) AC adaptor. A regulated AC adaptor guarantees that the output voltage will always be constant.
   
   Regulated adapter can be used in placed of an un-regulated adaptor. However NEVER replace a regulated adaptor with an un-regulated adaptor as this may damage the equipment.
   
   
4. Output plug size:
   
   There are hundreds of different applications that use mains adaptors and you will note that there are a number of different output plugs. We offer a range of universal adaptors each supplied with a range of Jack Plugs that should fit most of the applications. A plug size of 2.1 x 5.5mm means that the inner diameter is 2.1mm and the outer diameter is 5.5mm.