Testing human reaction speed is not only a fun way of spending time, but also allows the drawing of conclusions, for example on the skills of a momentary driver. When the contact closes the power button, the astabil multivibrator built with IC1 produces pulses that are applied to counter IC3. D1 …. D10 LEDs light up sequentially in a chained fast.

This fatigue testing circuit is very simple and easy to build and will determine how tired a person is. It has been discovered that the highest light frequency that a human can detect is negatively influenced by his fatigue. This circuit is based on 555 timer that is connected here as an astable multivibrator. Its output is connected to a LED that is flashing with a certain frequency.