NE555 flashing light circuit diagram

When the circuit in the picture is working normally, the two LEDs will flash one after another at the same time. The working principle of this circuit is similar to that of the 555 audio oscillator introduced in relevant newspapers and magazines. The difference is that the capacity of capacitor C1 is increased to 4.7uF. Therefore, the oscillation frequency of the circuit is very low, and the speed of the potential change of pin 3 of NE555 slows down. When pin 3 outputs high level, the light-emitting diodes VD1 and VD2 are powered on and emit light at the same time. When pin 3 outputs low level, both LEDs will go out. The greater the resistance value of R3 in the circuit, the smaller the luminous brightness; the smaller the resistance value of R3, the greater the luminous brightness.

It is worth noting that the resistance of R3 should not be too small, otherwise the current flowing through the light-emitting diode will be too large and the circuit will consume a lot of power, which will have an adverse effect on the light-emitting diode and even burn it out. Usually, the current flowing through the light-emitting diode can be controlled between 10 and 20mA.

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