An LED's brightness is directly proportional to the current through it, which creates a challenge for low-voltage and battery-powered applications. But it's possible ...

[Dr. Shane] asks the question: what happens if you connect the output of an inverter logic gate back to the input? In theory, it doesn’t make sense, but depending on the gate’s physical construction, ...

This design combines power-on and low-battery indication, can operate with any battery voltage up to 15V, has very low current drain (2mA or less) and costs less than $3.50 with new parts. When the ...