External power supplies are mains adapters and power units that convert 230 V AC into DC for laptops, monitors, routers and electronics equipment. Our range has over 70 models, mostly from DEHNER, MEAN WELL, VOLTCRAFT and PULS. The category suits anyone replacing a laptop charger, as well as those who need a supply for industrial or DIY projects.
How to choose an external power supply
Output voltage. The voltage must match the value printed on your device's label or in its manual. Laptops often need around 19 V, while LED strips, cameras and industrial automation usually run on 12 V or 24 V. A voltage that is too high can damage the equipment.
Power and current. The supply's maximum current must be at least what the device needs, and a little extra only adds headroom. If the device needs 3 A, it is safer to choose a supply rated for 3.5 A or more, since it will then run well below its limit and stay cooler.
Connector and polarity. Laptops need the exact plug in terms of diameter and pin layout. Industrial supplies usually have screw terminals, so the cable must be connected according to the markings. Check polarity before buying, as the positive contact can be in the centre of the plug or on the outside.
Housing type. A desktop brick with a cable suits a computer or monitor, a plug-in adapter goes straight into the socket, and a DIN rail supply mounts in a control cabinet. Open-frame and built-in units are meant for manufacturers who fit them inside their own device.
Protections and efficiency. Look for protection against short circuit, overload and overheating. Higher efficiency means less waste heat, which matters in closed cabinets and for equipment that runs around the clock.
Brands in our range
- MEAN WELL: a Taiwanese manufacturer known for industrial power supplies, LED drivers and DIN rail units.
- PULS: a German company that specialises in DIN rail power supplies used in industrial automation.
- VOLTCRAFT: the Conrad Electronic house brand, which includes laboratory power supplies and universal adapters for electronics.
- TELTONIKA: a Lithuanian maker of networking and telematics equipment, with power supplies for its own routers and devices.
- FUJITSU TECHNOLOGY SOLUTIONS and IIYAMA: computer and monitor manufacturers, whose power adapters suit equipment from the same makers.
Also in our range: DEHNER (including DEHNER ELEKTRONIK), COREPARTS, SYNERGY21, QOLTEC and EDAC.
Frequently asked questions
Can I use a more powerful power supply than my device needs?
Yes, as long as the voltage matches and the supply's current or wattage is higher than the device requires. The device only draws the current it needs. A higher voltage than specified is dangerous and can damage the equipment.
Will another manufacturer's charger work with my laptop?
It will if the voltage, plug and polarity match and the power rating is at least that of the original charger. Some manufacturers add an identification pin to their chargers, so such laptops may run slower or not charge the battery fully. Compare the markings on the labels first.
What is the difference between a DIN rail supply and an ordinary adapter?
A DIN rail supply clips onto a standard rail in a cabinet and connects with screw terminals, while an ordinary adapter plugs into a socket. The first is made for automation and industrial equipment, the second for computers and household electronics. Many DIN rail supplies also have an adjustable output voltage.
How do I work out what wattage I need?
Multiply the voltage by the current shown on the device label. For example, 19 V and 3.42 A gives about 65 W. Choose a supply with the same rating or slightly higher.
