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Can you connect two adapters together?
No, you should not connect two adapters in parallel. If there is any unbalance at all there will be current from one to the other and you will not get the increased current. No two adapters will have exactly the same voltage output, the higher voltage unit will provide more current than the one making a millivolt less.
Can you stack adapters?
There is no problem stacking adapters as long as those adapters are good quality. I use stacked adapters quite regularly.
Is it safe to use multiple adapters?
Yes, it’s generally safe. Adapters don’t have any active components, so assuming they’re all rated for the voltage/amps you’re putting through, there’s little risk of overload etc like there is with transformers.
How does an AC DC power supply work?
An AC-DC power supply can exist as a separate module or be included within the appliance itself. Either way, they operate by converting the AC voltage to the required output level, rectifying the sinusoidal voltage, and smoothing the peak to provide a linear, stable DC output.
How are power supplies isolated from each other?
RE ISOLATION Note the drawing below, both power supplies have their negative outputs ties to mains ground. When wired up this effectively shorts the output of the virtual rail to the negative terminals. As such you need to be sure things are correctly isolated in your circuit and internal to the supply.
Is there a limit to AC DC power?
AC-DC power supplies are designed to operate up to a maximum limit of current. Yet, there are occasions where the load could draw more current than is allowed, whether intentionally or not. You’ll need to ensure that the voltage is reduced to zero in the event of a short circuit or overcurrent.
How to make a split supply from a single supply?
Adding some load to the negative rail to ensure that it draws more current than the positive rail does is required to ensure regulation as the 7812 will not sink current. As Janka points out the positive rail will be unregulated. Here is a solution which uses two adjustable linear regulators (LM317/LM337) to form a virtual ground.