PSU / Combine 12v and -12v rails for 24v?

  • Thread starter Thread starter singlespeed
  • Start date Start date
  • Tags Tags
    12v
AI Thread Summary
Combining the -12V and +12V rails to achieve 24V does not allow for the high current of the +12V side, as the overall current is limited by the -12V side's rating, typically around 0.8A. For higher voltage outputs in the 14-16V range, using multiple power supplies in series may be possible if their outputs are floating and independent. However, many power supplies have their ground tied to the case and plug, which would prevent this configuration. An alternative is to invest in a decent adjustable two-channel power supply that can provide higher voltages and currents, typically priced between $150-$300. Ensuring proper setup and understanding the limitations of the equipment is crucial for achieving desired voltage outputs.
singlespeed
Messages
2
Reaction score
0
I would like to increase my voltage on these PSU's to 24v. If I combine the -12v and +12v for 24v do I still get the high current of the 12v side?

+12v 70A

-12v .8A

24v... but what is the current potential?

610200994548PM_0003-vi.jpg
 
Engineering news on Phys.org
do I still get the high current of the 12v side?
No you don't.

You must still respect the -12V side's current rating which is typically only half an Amp or similar, so that will set your overall current rating for 24V operation. Note that you also require a floating (non ground referenced) load for it to work, this part is very important!
 
uart said:
No you don't.

You must still respect the -12V side's current rating which is typically only half an Amp or similar, so that will set your overall current rating for 24V operation. Note that you also require a floating (non ground referenced) load for it to work, this part is very important!

Thanks for the reply, I figured it would inherit the lower amp side. Is there any way I can boost the current voltage to above 12? I'd like to see it slightly higher in the 14-16v range.
 
ASSUMING the outputs are floating and completely independent, you may be able to put the power supplies in series (as you would with two 12V batteries). You should be able to use a mutlimeter (with the supplies turned on) to see what the voltage is between one supply's 12V supply, and the ground (or 12V output) of the other. If it's anything but open circuit, then a connection exists between the two of them.

Unfortunately, I suspect all of these will have the ground output tied to case and the ground prong on the plug, and hence be connected through the ground line, and you won't be able to do what I suggest above. A decent (current-limiting, short circuit protecting, etc.) adjustable two-channel power supply (up to 30V) will only run you around $150-$300 new, and possibly less somewhere like eBay. However, most of these will only supply 3 or 5A max, per channel (though you can connect them in series to get up to 60V, or put them in parallel to get 6 or 10A).

EDIT: Finished dangling thought
 
Very basic question. Consider a 3-terminal device with terminals say A,B,C. Kirchhoff Current Law (KCL) and Kirchhoff Voltage Law (KVL) establish two relationships between the 3 currents entering the terminals and the 3 terminal's voltage pairs respectively. So we have 2 equations in 6 unknowns. To proceed further we need two more (independent) equations in order to solve the circuit the 3-terminal device is connected to (basically one treats such a device as an unbalanced two-port...
suppose you have two capacitors with a 0.1 Farad value and 12 VDC rating. label these as A and B. label the terminals of each as 1 and 2. you also have a voltmeter with a 40 volt linear range for DC. you also have a 9 volt DC power supply fed by mains. you charge each capacitor to 9 volts with terminal 1 being - (negative) and terminal 2 being + (positive). you connect the voltmeter to terminal A2 and to terminal B1. does it read any voltage? can - of one capacitor discharge + of the...
Thread 'Weird near-field phenomenon I get in my EM simulation'
I recently made a basic simulation of wire antennas and I am not sure if the near field in my simulation is modeled correctly. One of the things that worry me is the fact that sometimes I see in my simulation "movements" in the near field that seems to be faster than the speed of wave propagation I defined (the speed of light in the simulation). Specifically I see "nodes" of low amplitude in the E field that are quickly "emitted" from the antenna and then slow down as they approach the far...
Back
Top