Changes

The binary states of 1 and 0 indeed represent high and low voltages (typically 3V/5V and 0V) , respectively, at the pins of a digital device. When the input pin of a digital device changes its state, for example, from low to high, the device’s output pin does not change its state instantaneously. It takes a finite amount of time for the device to react to the state change. This is called the propagation delay. Digital devices may have different propagation delays for change of state from low to high (TPLH) or change of state from high to low (TPHL). As you connect and cascade many digital devices, these propagation delays add up and amount to a sizable delay time. In high-speed digital circuits, where state changes may occur very fast, the accumulated propagation delays may create serious operational problems.

==Wire and Pin Values (Level & Strength)==