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Can I connect multiple DC adapters in series to get higher voltage?

Can I connect multiple DC adapters in series to get higher voltage?

Old 08-03-18, 12:16 AM
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Can I connect multiple DC adapters in series to get higher voltage?

Can I connect multiple DC adapters in series to get higher voltage?

Hello everyone

So I have many 12v 500mA DC adapters that came with old ADSL modems and Ethernet switches and I was wondering if I can connect two or three of these adapters in series, kinda like connecting DC batteries, to get higher voltage. Im not looking for like 24v or 36v /500mA exactly. Im just wondering if connecting them this way is safe and would in fact yield higher voltage. I get that it might not be an exact output and the lower amp might be an issue and all of that and I'll of course be measuring the output before using it.

Thanks in advance
Old 08-03-18, 02:26 AM
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Yes, but you need to figure out which wire is positive / negative and then connect the neg. from one to the pos. of the next one. If you connected them in parallel voltage would remain the same but Amperage would increase
Old 08-03-18, 03:54 AM
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IMO, strictly a paper exercise, nothing that should be wired up and plugged in. Far too easy to get a single adapter to deliver the voltage you need.

Technically, if you had the schematics for what is inside the lower voltage adapters you might be able to connect them in series. However, if that jury-rigged shortcut were to catch fire you and only you would pay the bill. An easy out for the insurance company.

Old 08-03-18, 06:46 AM
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CAN you? of course.

From a safety viewpoint, the picture changes a bit. If we are considering marketing such a contraption, the rules significantly change once you exceed about 48V total, depending on the application.
Technically, if Class 2 devices are used, then they have very significant isolation ratings that they need to already meet, and series connections to get a reasonable voltage will not cause insulation breakdown.
Old 08-03-18, 12:45 PM
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Another problem with plug in power supplies is that they aren't all designed the same. There are two basic styles.... one that uses a standard transformer with a rectifier and filter capacitor. Then there is the newer style that uses high voltage electronic switching. Those two styles can never be connected together at all.

The newer style adapters are easy to spot as they say "input voltage from 100-240vac" on them.

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