In the design , 555 timer is used in an astable vibrator circuit that will drive four different LEDs with different series resistors. These four LEDs should be the same color and it will show you how brightness varies with different series resistors. I have added isolation switches, indictor LEDs and test points as well for analysis

The main purpose of your board is to show the impact of good and bad layout techniques in reducing the switching noise. The key feature of this board is that we have two identical hex inverter circuits. 

• For one circuit, the layout has been designed with best design practices: continuous return plane and decoupling capacitor close to the IC’s power pin. 

• But in the second circuit, bad practices are used: There is no ground plane under the IC and only a trace to route the ground connections. And the decoupling capacitor is far away from the IC pin.

The main purpose of the board is to design an Arduino board using the best design practices. Thus it will show a reduction in crosstalk (ground bounce) and reduces power rail switching noise from I/Os switching compared to the commercial Arduino available in the market. 

The main purpose of the board is to design a 4-layer board with a microcontroller and data acquisition system, an instrument droid. This is a custom instrument designed specifically to characterize any voltage source, or voltage regulator module (VRM) by measuring its Thevenin voltage and the Thevenin resistance as a function of output current.