This LED DC voltage indicator circuit is a voltmeter, rather than simply a battery tester. As such it may measure voltages as low as 3V. It utilizes venerable LM741 operational amplifiers applied as ...

There are many applications where the accuracy of a digital or analogue (bar graph) is not required but something better than a simple low/high indicator is desirable. A battery charge level indicator ...

The following circuit uses a low-power CMOS comparator and an LED to indicate low-battery voltage without causing excessive current drain. To view the application note, click on the URL below. Circuit ...

I needed a simple LED indicator showing that a particular voltage level had been reached—specifically, that a capacitor had charged to a particular potential. I was convinced that there must be a way ...