# Combining a benchtop power supplies

So I made an error when purchasing a power supply that was far below desired voltage (dc). The power supply I bought certainly produced enough current, however, and I am wondering if it is possible to combine this power supply with a second power supply for the voltage without blowing both of them. I am powering several stepper motors at the same time as well as providing a 10V barrel jack plug in. I don't know if this is possible and instinct is telling me that I will explode one or both of the supplies if I place them in series to the circuit and at least one if they are in parallel but I have no good way of explaining why I feel this way. If someone wouldn't mind explaining if this is even possible, and if not what goes wrong, that would be awesome.

You can place the two outputs of the supplies perfectly in series with no problem think of it like batteries. when you place them in series you just add the voltages together 12V + 12V = 24V

• So even though one of them is producing mostly current and one of them is producing mostly voltage this won't cause an issue? Also, I understand the voltages will add but the current should average correct? Could this cause any damage to the smaller current producer? – MJAFort Jul 28 '15 at 19:56
• If they are in series, the current through each power supply is the same. There should be no damage if each supply is operating within its specified voltage and current ratings. It is assumed that none of the power supply outputs are grounded. – Barry Jul 28 '15 at 20:28
• Right, duh, but would this mean that the smaller one has all the current of the larger one going through it? Sorry, I'm really slow today and momentarily forgot about kcl. I guess what I'm asking is will the second power supply be able to deal with the higher amperage? Does it have the tolerance? – MJAFort Jul 28 '15 at 20:40
• @MJAFort - Bruce's answer assumes two things: (1) the power supplies are isolated from their input ground and (2) that the supplies all can provide the needed current. If you need 10V @ 2A, each supply must be individually able to produce 2A and the sum of the voltages must be 10V. – DoxyLover Jul 28 '15 at 20:59

Another approach. ( assuming you have enough wattage) would be to use a boost converter to increase the voltage at the expense of some current. This negates the need to purchase another PSupply.

• So just quickly, if I were to take a few of these and put a few of them in parallel to drive different motors or sets of motors I would probably be fine? – MJAFort Jul 29 '15 at 15:21
• In principle yes that should work so long as you didn't exceed your current limits. – BenG Jul 29 '15 at 21:40