If you can connect three 9V batteries in series to obtain a 27V DC source, can you do the same thing with AC input to DC output power supplies? What are the potential problems with the power supplies themselves (ie: can you ruin them doing this)?
Can you stack unlike DC outputs? Will a 12VDC supply connected in series with a 4.8VDC supply give you a 16.8VDC supply? Are there potential problems with the supplies themselves if each has different power outputs, say 12VDC @ 500 mA with a 4.8VDC @350 mA?
2006-12-02 09:23:36 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Yes, it's possible. Yes you can ruin them if you are not careful particularly if they have a DC earth connection to the case , these are usually decoupled by a big electrolytic capacitor and if you tie +ve to -ve in a big chain then let the cases touch you could blow the capacitor - if they all have insulated cases this is less likely. The other thing you can do is inadvertently connect them in parallel - not good. If you are careful then you shouldn't have a problem until the peak voltage starts to get close to the breakdown voltage in your least robust transformer. If they are not particularly well regulated you can get some fairly bizarre harmonics from all of the ripple on your nominally DC outputs.
If you are happy with all of the above then the maximum current draw capacity is going to be set by the least rated supply and when the thermal trip goes on this there is still the possibility that, although the end-end voltage drops there is still enough current being pulled through the tripped supply to melt something.
The very last thing I can think of is that some programmable power supplies actually have the control and monitoring link ground referenced to DC ground so it is possible to blow the interface card if you are not careful.
There are usually a load of old mobile phone chargers lying around that no one wants any more and you can cut open and experiment with - Best of Luck
2006-12-02 09:56:51 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Power supplies aren't the same as batteries. They are feedback controlled devices that adjust their output based on what they "see" at their output versus what they are supposed to be kicking out. It's not a good idea to series them.
2006-12-02 09:35:26 · answer #2 · answered by Ken 2 · 0⤊ 1⤋
The outputs must be isolated from ground since you're plugging them into the wall, and you must not exceed the voltage limit between the output and the grounded case.
2006-12-03 04:50:14 · answer #3 · answered by Dr. R 7 · 0⤊ 0⤋
You can if their design is adequate. Read the manuals. If you're talking about the simple wall-mount dongle supplies, they are most likely well isolated and would work fine. Don't expect them to be well-regulated.
2006-12-02 13:40:51 · answer #4 · answered by Frank N 7 · 1⤊ 0⤋