Transistor Capacitor Timer LED Blinker

A capacitor-based timer LED blinker is one of the simplest circuits you can build: it uses a resistor-capacitor (RC) network to charge and discharge periodically, controlling a transistor or timer IC to switch the LED on and off. You can achieve this either with a single transistor and capacitor or with a 555 timer IC in astable mode, depending on how precise you want the timing to be.