You know how it is. You’ve got that new project running, and while it doesn’t consume much power, it also doesn’t give much indication of whether it’s functioning or just sitting there with a dead ...

Signals when an on-circuit battery is exhausted, 5V to 12V operating voltage A Battery-status Indicator circuit can be useful, mainly to monitor portable Test-gear instruments and similar devices. LED ...

In this flashing led lights circuit, the LDR or photoresistor is connected in such way that when the light intensity varies it will influence the flashing frequency and the brightness of the LEDs. T1, ...

It is a pretty common first project to use an Arduino (or similar) to blink an LED. Which, of course, brings taunts of: you could have used a 555! You can, of course, also use any sort of oscillator, ...