From the PyroEDU tutorial for the 555 Timer
How I think it works, please correct me if I'm wrong.
Switches back and forth. If built on a breadboard, would look like 2 lights that flop back and forth on and off based on when the capacitors discharge. As the capacitors discharge, they turn on the transistors, which complete the circuits for the LEDs.
When the capacitors are depleted, the transistors shut off the flow of current, and the capacitors recharge. At a threshold, the capacitors discharge, completing the circuit, and cycling appropriately over and over.
If you increase the capacitance on the two capacitors, the lights will blink left and right with less frequency. This is because each capacitor has more time to recharge before dissipating, thus turning on the transistor, which completes the circuit, lighting the LED, which in turn, drains the capacitor to the point in which the transistor switches off.
