An AA, AAA, C, D, or 9V battery comprising: a housing ; a positive terminal ; and a negative terminal ; wherein the housing contains: a power source ; and a voltage regulation device that is operatively connected to the positive terminal , the negative terminal and the power source , wherein the battery has an output voltage and an output current between the positive terminal and the negative terminal in use, and further wherein the voltage regulation device includes: electronic components that are operatively connected to each other to regulate the output voltage to a programmed variable level; a current sensing circuit that is adapted to sense the output current or a current of the power source of the battery ; a controller that is operatively connected to one or more of the electronic components of the voltage regulation device; a buck regulator configured to selectively provide the output voltage; and a linear regulator configured to selectively provide the output voltage, wherein when the output current or current of the power source is below a pre-determined threshold, the controller is configured to disable the buck regulator and enable the linear regulator, and when the output current is above the pre-determined threshold, the controller is configured to enable the buck regulator and disable the linear regulator. a housing ; a positive terminal ; and a negative terminal ; wherein the housing contains: a power source ; and a voltage regulation device that is operatively connected to the positive terminal , the negative terminal and the power source , a power source ; and a voltage regulation device that is operatively connected to the positive terminal , the negative terminal and the power source , wherein the battery has an output voltage and an output current between the positive terminal and the negative terminal in use, and further wherein the voltage regulation device includes: electronic components that are operatively connected to each other to regulate the output voltage to a programmed variable level; a current sensing circuit that is adapted to sense the output current or a current of the power source of the battery ; a controller that is operatively connected to one or more of the electronic components of the voltage regulation device; a buck regulator configured to selectively provide the output voltage; and a linear regulator configured to selectively provide the output voltage, electronic components that are operatively connected to each other to regulate the output voltage to a programmed variable level; a current sensing circuit that is adapted to sense the output current or a current of the power source of the battery ; a controller that is operatively connected to one or more of the electronic components of the voltage regulation device; a buck regulator configured to selectively provide the output voltage; and a linear regulator configured to selectively provide the output voltage, wherein when the output current or current of the power source is below a pre-determined threshold, the controller is configured to disable the buck regulator and enable the linear regulator, and when the output current is above the pre-determined threshold, the controller is configured to enable the buck regulator and disable the linear regulator. <EOS>