| Electronics > Beginners |
| Can I get 5V 2.5A from a 12V 1.5A power brick? |
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| mikeselectricstuff:
--- Quote from: Hero999 on August 16, 2018, 01:44:42 pm --- If only 5V 2.5A is required, then use a 5V brick. Converting 12V to 5V, when it's not necessary is bad design. --- End quote --- Unless you have any significant cable length. Local conversion at the load end both reduces losses and gives you tolerance of voltage drop. |
| Zero999:
--- Quote from: mikeselectricstuff on August 16, 2018, 02:49:45 pm --- --- Quote from: Hero999 on August 16, 2018, 01:44:42 pm --- If only 5V 2.5A is required, then use a 5V brick. Converting 12V to 5V, when it's not necessary is bad design. --- End quote --- Unless you have any significant cable length. Local conversion at the load end both reduces losses and gives you tolerance of voltage drop. --- End quote --- That's true, but wouldn't it make sense to use an even higher voltage in that case? I suppose 12V might be more optimal, because a simple buck converter can convert 12V to 5V more efficiently, than 24V to 5V. |
| james_s:
It would also make sense if you happen to have some nice 12V power supplies already, or if something else you also want to power requires 12V. |
| Zero999:
--- Quote from: james_s on August 16, 2018, 05:13:17 pm ---It would also make sense if you happen to have some nice 12V power supplies already --- End quote --- That's what I was thinking, but would disagree with it being a good reason for this. It will probably not cost much to buy the correct power supply and save the 12V ones for another project. In the past I've made some poor design choices because I resorted to using what's available, rather than being more patient and ordering the correct part. Fair enough, the part is expensive or takes too long to get, then it makes sense, otherwise it's generally better to wait and spend a little. --- Quote ---or if something else you also want to power requires 12V. --- End quote --- That makes more sense, but if the 12V device is small, compared to the 5V device, it begins to make more sense to use a 5V PSU and a boost converter. Of course this is assuming the cable length is short, otherwise it's better to transmit the power at a higher voltage, though a long cable, as previously mentioned. |
| technix:
--- Quote from: Hero999 on August 16, 2018, 01:44:42 pm ---Why not simply use a 5V 2.5A brick? That's got to be the easiest solution. Is there a requirement for 12V? If so, what current? Then the question is whether it's better to use a 5V brick and boost to 12V. If only 5V 2.5A is required, then use a 5V brick. Converting 12V to 5V, when it's not necessary is bad design. --- End quote --- --- Quote from: james_s on August 16, 2018, 05:13:17 pm ---It would also make sense if you happen to have some nice 12V power supplies already, ... --- End quote --- I just happen to have a bunch of 12V 1.5A and 12V 2A power bricks in spare. Here in Shanghai those are handed out as part of standard telecommunication hardware from China Telecom, but those field service engineers just never bothered to collect them when returning devices for upgrades or repairs, allowing them to accumulate here. --- Quote from: james_s on August 16, 2018, 05:13:17 pm ---... or if something else you also want to power requires 12V. --- End quote --- There is nothing that requires 12V in this LED strip. --- Quote from: mikeselectricstuff on August 16, 2018, 02:49:45 pm ---Unless you have any significant cable length. Local conversion at the load end both reduces losses and gives you tolerance of voltage drop. --- End quote --- Is 1.5 meters to 2 meters a significant cable length? The copper might be thin though, being Chinese-made el cheapos. |
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