Chapter 139

2 AA cells replace 9V battery, extend operating life

Steve Pietkiewicz


Replacing a 9V "transistor" battery with 2 AA cells and a step-up switching regulator can provide significant gains in battery life as well as cost savings. Three approaches with a 30mA load are illustrated and compared.


9V battery

AA cells

operating life

Operating life is an important feature in many portable battery-operated systems. In many cases the power source is the ubiquitous 9V “transistor” battery. 5V generation is accomplished with a linear regulator. Significant gains in battery life can be obtained by replacing the 9V/linear regulator combination with 2 AA cells and a step-up switching regulator. Two (alkaline) AA cells ...

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