This is a simple flashing led circuit with 2 leds and 2 NPN transistors. It illustrates the behavior of transistors and capacitors and if you use an oscilloscope it will be very easy to determine what ...

This simple Mock Flasher LED simulates the indicator of a sophisticated Alarm system. It can be placed in doors, gates and vehicles to confuse intruders.

In Figure 1, National Semiconductor's LM3710, a supervisory circuit, is configured to reduce the power consumption of a traditional LED indicator by 99%.

They look for all the world like any other LED, though embedded in the plastic dome is an integrated circuit to do all that flashing work.

[Big Clive] also does his customary reverse-engineering of the circuit, which is just a simple flasher powered by USB-C.