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 ...

This simple water level indicator will activate an active buzzer (e.g. BeStar BPT-23CX ) in order to make a noise when a certain level of water is being reached. Because the water sensor and the ...

Often, the only liquid level indicator you need is your eyes, such as when looking at your cold beverage on a summer’s day. Other times, though, it’s useful to have some kind of indicator light that ...

If you’re working with 3.3V or 5V circuits, it’s easy for you to throw on a power or status LED here or there. [Tom Gralewicz] has found himself in a pickle, though, often working on projects with ...