Hey all. I have a power brick which i thought was 12 volts 1.2a. But when i put my meter on it reads 14.4volts. Am i missing something?
1 Like
It is what it is.
Many adapters specify the approximate, average voltage under load, and the open circuit voltage (as read by a multimeter) can be much higher than what is printed on the package.
Perhaps your adapter is meant to charge a "12V" lead acid battery, which actually requires over 14V.
1 Like
Depending on how well it's regulated the voltage may be higher with a light load (or no load) vs. at or near the maximum 1.2A rating.
And/or there will always be some tolerance/variation from the nominal rating.
More than 1V off at 12V is not great by today's standards...
It used to power an old electric piano. Would using a buck converter to stabilise to 12v be a good option?
How do you plan to use the brick?
The "VA" is short for "VoltAmpère" and is similar to Watt.
12V times 1.2A makes 14.4 Watt. But "Watt" does not tell the whole picture, so often "VA" is used. However, the "VA" for a output with a fixed voltage is weird.
The open output voltage of 14.4V is by pure coincidence the same number.
The output voltage of a power adapter is often 1% or 2% higher to compensate for loss in wires.
This adapter might have a questionable circuit or your multimeter is too cheap. It does not seem to have good certifications. The "CE" logo does not mean that it is good quality.
2 Likes
Im building a 8mm cine scannerscene. The stepper
Precisely pulls the film over the scanner while one dc motor is the takeup real. Collects the scanned film. The other dc motor rewinds the film back onto its original reel.
Thanks for the reply. Iv just ordered a new brick of amazon which has great reviews. But this one is 3Amps. Am i right in assuming that my devices will only draw what they need and no more? Well except the stepper driver. But that has a current limiter on it which ill have to setup
For that, you need to first characterize the average current draw of all the components during typical operation, including voltage regulators, then size the base power supply appropriately.
Usually the base power supply is chosen to provide at least 2X the average current.
2 Likes
Note the AC voltage. 230volt AC.
This is an old-style transformer-base brick, maybe with some internal regulation.
Unloaded voltage of those old bricks is often 40% higher than what's on the label.
Modern universal voltage supplies (85-260volt) are much tighter regulated,
and therefore much safer for electronics.
Leo..
1 Like
Weird for DC in fact! 
1 Like
but not at all unusual to indicate how the device will load the mains gpo
[powerpoint]
Hi,
That device has the Chinese Export CE on it for a start, so they could quote the power rating in any units they like and as confusing as they like.
14.4VA is probably on the wrong line and should be up where the Input figures are.
Tom... 
2 Likes
Thanks China 
for confusing an already confused man.
1 Like
Is there any difference between VA and W?
The 14.4 VA is surely output - 1200 mA @ 12 V is 14.4 W, the input must be more.
it's just a cheap "60 plus turd" non-switching coil power supply. We use them all the time everywhere where the cost can't justify a switching power supply (especially a high quality one)
Which act a bit like a battery with super large internal resistance.
The output voltage drops as soon as it have a load and thus to actually deliver 12V at 1.2A the unloaded voltage is probably higher.
Not for DC!
1 Like
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.