It normally takes two transistors to build a blinker circuit (in order to make positive feedback possible). However, you can also use a photo-resistor (LDR) that is illuminated by an LED. The feedback ...

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 ...

Ordinary LED flashers turn the LED on and off abruptly, which can get a little irritating after a while. The circuit shown here is more gentle on the eyes: the light intensity changes very slowly and ...