555 Timer Dual LED Flasher

Here is a 555 timer circuit that flashes dual LEDs using a single output. In GCSE, it is important to understand the principle that you can connect devices to the output pin in this manner. When the output is logic 1, the output pin will produce a positive voltage close to the supply rail, and the current will flow through the lower resistor to ground lighting LED 2. However, when the output is logic 0, the potential at the output pin will be close to ground (0 V), and therefore current will flow from the positive supply rail, through the top resistor lighting LED 1.

Some interesting experiments you could carry out are to connect multiple LEDs in parallel, or change the values of R1, R2, and C1 to see how the LED blinking changes.

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