Looking for a mains switch inthe dark is easier if the switchcontains a built-in neon or filamentminiature lamp. Adding a small indicatorto any mains switch is helpful. It iseven better if the ...

An LED is commonly used as a "power on" indicator for many electronic devices. For the LED to produce discernible visible light in daylight, the forward-bias current needs to be in the moderate range ...

Here is a VLF receiver tuned to 300 kHz designed to detect the crackle of approaching lightning. A bright lamp flashes in sychrony with the lightning bolts indicating the proximity and intensity of ...

These days, if you want to flash some LEDs, you’d probably grab a microcontroller. Maybe you’d go a little more old-school, and grab a 555. However, [Jacob] is even more hardcore than that, as ...