Question is about those LED drivers that convert 120V (or whatever your house voltage is wherever you are) AC to 12V DC for driving LED light strips and the like.
Do they draw power when plugged in, but not loaded, i.e. the lights are turned off (switch on DC side)? If so, do they draw full power (e.g. 100W), or some kind of standby level of power?
TIA.
Best Answer
12V constant-current power supplies have a small "standby" power usage of a watt or three depending on quality, when all the DC loads are switched off. You can measure this by plugging it into a Kill-a-Watt. Other than that, they draw whatever power is used on the DC side, plus a few percent for conversion losses.
12V LED strips typically use a constant-voltage power supply, which is simply called a power supply. They are often marketed as "drivers" because it sounds cooler, but that's wrong. Any 12V power supply will work for LED strips.
(a real driver is a constant-current source and must be custom-matched to a very particular array of raw LEDs. LED strips don't work that way).