I saw an LED that just being connected to a source with a resistor just keeps flashing. How to do this?"
Common LEDs are formed by a simple chip of semiconductor material that needs a direct current to emit light. However, there are LEDs that incorporate an integrated circuit chip in the same emitting chip that makes them flash. In other words, they are formed by the LED and the flashing circuit. For these, just feed the circuit and it will flash the LED. A common LED, without this circuit, does not flash, simply light up. If we want to make it flash, we need the external circuit, for example with a 555. 4093, transistors and many others that the reader can find on the website.
