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  • How to create +/- voltage using one power supply

    nunorvoliveira is right:as soon as you apply asymmetrical load your virtual mass point will shift massivly. Of course a resistor divider still works as you. The only problem is as soon as the circuit you power from this divider is becoming more complex, your divider no longer is a simple divider, but a bigger more complex circuit.So using a resistor divider might be okay for something very simple (say powering a few LEDs), but if you wanna power something meant for audio (opamps) or even mikrocontrollers, this is definitly a very bad idea.A really good solution for low power applications is a opamp-buffered virtual ground point, this is however limited to the current the opamp can supply. If you wanna have more power (let's say 1.5A for each rail), one could use a combination of the LM3...see more »nunorvoliveira is right:as soon as you apply asymmetrical load your virtual mass point will shift massivly. Of course a resistor divider still works as you. The only problem is as soon as the circuit you power from this divider is becoming more complex, your divider no longer is a simple divider, but a bigger more complex circuit.So using a resistor divider might be okay for something very simple (say powering a few LEDs), but if you wanna power something meant for audio (opamps) or even mikrocontrollers, this is definitly a very bad idea.A really good solution for low power applications is a opamp-buffered virtual ground point, this is however limited to the current the opamp can supply. If you wanna have more power (let's say 1.5A for each rail), one could use a combination of the LM317 and LM337 voltage regulator, which will even deliver a more stable power supply (see this circuit http://www.goldpt.com/virtual_ground_circuit.html...If you are good with higher voltages and don't need to operate from battery you can also use a Transfromer with ±15V, which you rectify and stabilize again with LM317 and LM337 to create what is called a "Linear Power Supply".The differences between these different supplies is not only hearable and measureable, but they will also have a big impact on the stability of the circuit.

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