..... Something missing from the left column menu? Please tell us.
Technical Index Aerial+LNB 1 Cable Aerial amplifier Aerial Filters Aerial Groups Aerial Points Aerial - Which? Amp Adder Analogue Switch-Off A18QR aerial Arcon Dish Atticbox Audio Adapter USB AV equipment BBC/ITV outside UK Bedroom sound Best aerial Cable Kinked Cable specs Cable-Thin Coax Cable - Which? CAMs etc. Capacitor Kits Channels Chimney Brackets Coaxial Cable Cooling fan Compass use Cupboard Control DAT45 aerial DC inserter Decouple cable Denso Tape Digibox in loft Digisender Digital Ariel Diplexers DirecTV Disconnect safely Disguise a dish Dish indoors Dish Painting Dish Sharing Dish Size E-books Electric shocks Electronic Kits Electronic Parts Epoxy resin glue Extend cable Extender Plate F1 for Free Filter-notch Fire Hazard Fit F Connectors Fit TV plugs Foxsat HDR Free channels Freeview/Freesat Freeview Problem Freesat Install DIY French sat TV German sat TV Greek sat TV Heatshrink Sleeving Hole Cover Humax PSU Inside Sky Digibox Instructions Interference Invacom LNB Italian sat TV IR sensor-locate Large Dishes Lightning Protect Liquid Spilt LNBs - about LNBs - add more LNB amplifier LNB Boots LNB Fitting LNB-Replace Sky LNB Reset LNB skew LNBs-Switching two LNBs 2 in 1 cable LNB-waterproof your Loft Boxes Magic eyes Make Fly-Lead Multiroom phone Multiswitches No Satellite Signal Omnisat Semitronic Orbital dish Phone Socket Wires Phone surge protect Plate-Twin-F Plugs-which? Plug-Top PSUs Plus Combiner Powermid+cable TV Powermid XL Reed Switches Remote Codes Remote Eyes Remote extenders RJ45 plugs Satellites-where Scart leads Self-Amalg Tape SelfSat Antenna Signal Combiners Signal Meter Silicone Grease Sky x2 same room Sky+ batteries Sky Digital Sky in Europe Sky Install DIY Sky LNB Sky LNB-extra Sky Multiroom Sky Remote Probs Sky room wiring Sky Plus Solder - How to Split Digibox RF Split Dish cable Split satellite signal Stacker-Destacker Stuck in standby Thomson Problems Tree blocks signal Triax minidish TV/VCR faults TV Links tvLINKplus TV set New TV eyes USALS Videosenders VisionLink Wall Plates WF125 Plugs What Channels Which plugs Wire my house 304114 wall plate Shop Index Checkout All Aerials Aerial Amplifiers Aerial Attenuators Aerial Boosters Aerial Filters Aerial Hardware Aerial Meters Aerial Splitters Audiophile Bargains Books to download Boosters, Amps Cable & Extensions Cable Joint Cable on Reels Capacitors Caravan/motorhome Car Radio Adapters CAT5-HDMI Components Computer Batteries Computer Leads Digibox spares DiSEqC Switches Dishes Dish Hardware DVD Players Earth rod Electrical - mains Electronic components Electronic Kits Electronic Kits 2 Extension - Coax Extension - mains Faceplates Filters electrical F Plugs Fly Leads Freeview cable Freesat Digiboxes FTA Digiboxes Freeview receivers Fuses Gaming Accessories German Sat TV HDMI / Audio Headphone Amp Home Cinema Installation kits Leads + Plugs LED Torches LNB cable LNBs for Sky LNBs 40mm LNBs C120 LNB switches LNB amplifiers Loft Boxes Magic Eyes Mains Electrical Meters Motorhome Motorised dish bits Multiswitches Power supplies Remote Controls Remote extenders Resistors RF Cable RF Modulators Satellite Cable Satellite Meters Scart Leads Screen Cleaning Signal Combiner Sky Digiboxes SkyLink Amplifiers SkyLink Bypass Splitters Telephone cable Thomson PSU Tools Grease Glue Transistors TV Eyes TV Plugs TV Wall Brackets Videosenders Video/Leads Wall plates 1 Wall plates 2 Technical Index FAQs BLOG Contact Us		Tell me about plug-top Power Supply Units Firstly, you must label them before use so you know which equipment they match. I label mine with ordinary self-adhesive address labels. If these fall off (because of heat or plasticiser exuding from the material) then I glue them back on with "Bostick", "UHU" or similar. I have also used "masking tape". The key points to note when choosing a PSU are: 1. Is it AC or DC output? 2. If DC, is it regulated or unregulated? 3. What is the output connector type (and polarity if DC - usually centre is positive). 4. What is the maximum current it can supply?* The current rating should be equal to at least the maximum that the equipment will require. It does not matter if it is rated higher, except that you will probably be paying a little more for capability that you don't need. (Think of it as buying a bucket that is larger than you will ever need.) This is often labelled as a WATT or VA rating. Watts = Volts x Amps so, for example, a 12 volt power supply unit with a rating of 24 Watts (or labelled "24VA") will be able to supply 24/12 = 2 Amps of current. Some people refer to a PSU (Power Supply Unit) as "a transformer". Nowadays this is seldom correct, although the unit might contain a transformer as part of its circuit. A transformer passes only AC. Modern Power Supply Units are of a type called "Switch-Mode". They contain a bridge-rectifier (to convert AC to high-ripple DC) and a capacitor (to smooth out the ripple). This "raw DC" is then fed to the electronic switching circuit that "chops" the voltage at high frequency at around 350 volts. The resultant spikes are fed into a tiny transformer that changes the voltage to one or more lower voltages (which are still high frequency pulses). Then a rectifier and capacitor smoothes out the pulse chain into a DC voltage. Finally, if a steady (regulated) voltage is required, the current is passed through a voltage regulator circuit that removes any fluctuations. The reason for using a "Switch-Mode" PSU is that it is more efficient (wastes less power as heat) and physically smaller and lighter than a conventional PSU that used a transformer capable of running only at 50 Hz or 60 Hz. Go to PSU order page Send this page address - CLICK HERE - to a friend ! ©2011 SatCure