Battery Voltmeter Tester
The purpose of this project is to construct a quick and simple circuit to test the Batteries. The circuit amounts to a two-range DC voltmeter. The detailed description of the DC voltmeter circuit is included in other projects (such as project Capacitors Charge and Discharge in Capacitor Section) where a graph is included.
The full-scale voltages of this Meter are actually lower than the Batteries to be tested. Therefore, anytime the Batteries are not able to pin the Meter (when set on the proper voltage range), you know they are weak.
This Meter will help you troubleshoot a circuit that won't work, by determining if the Battery is at fault. With the Switch DOWN you have a low voltage range (3V), and with the Switch UP, the higher voltage range (9V).