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Regulated Power Supply Puts out 12.4V


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I have a 12v regulated PSU which puts out 12.4v on a very small load. Is this enough to damage anything and is there a certain amount of extra it needs to be under?

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A good regulated supply should output a rock solid X volts.  


Some PSUs will have a small pot that can be adjusted to adjust the voltage.  This is especially true of more inexpensive voltage regulators.  For example this one has a knob you can adjust:




while others may have a small 'Trimer Potentiometer' (a square looking thing) with a screw that adjusts.


Do you have a pic of your supply/regulator?

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As Mike said, a regulated power supply should output the same voltage regardless of the load.  In fact some fancy supplies remotely monitor the voltage at the load end of the power cable in order to compensate for the voltage drop in the power cabling.


Traditionally equipment designed for "12 volts" really operates on more like 13.5 or there abouts.  This is because most "12 volt" stuff was designed for a vehicle electrical system - which is typically 13.5 plus or minus a couple tenths when the engine is running.  In fact, a lot of 12V equipment really doesn't run all that well at 12 volts and would prefer something a bit higher.  Again traditionally almost all "12 volt" regulated power supplies normally actually supplied something between 13.5 and 13.8 volts.


With that said, there is an increase in equipment that was never intended to run in a vehicle and in some cases really is expecting 12 volts.  As a result, we are seeing an increase in power supplies that are actually putting out right around 12.0 volts.  This can cause problems for using these supplies with equipment designed for vehicle use (two way radios and stereo equipment come to mind).  Most of our LED lighting is in the category of equipment that was designed for 12 volt operation (as opposed for vehicular use) so it's perfectly happy at 12.0 volts.


In dumb strings and strips, there is normally only a current limiting resistor in line with the LEDs.  this means that as the voltage goes up, the current will increase rather quickly.  With most smart pixels or strips, the controller chip is regulating either the voltage or the current so the resulting change in current through the LEDs would be far less as a result in changes in supply voltage.  The controller chip itself of course also has a voltage limit, but as I understand it there is often a voltage regulator that protects the chip from high voltage.  Then the high voltage limit would be the regulator that is feeding the chip.  A little extra voltage will also help compensate for long cable runs.


With all the technical stuff, what all this means is that your equipment should be fine with a power supply supplying 12.4 volts - although you may be able to adjust that down a little if desired (I wouldn't bother).

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