Seven Segment is 8 pieces of LED array is arranged in such a way that was shaping up to 7 segments and 1 point that can be used to show the pattern numbers and some letters. there are two types of seven-segment LED Seven segment of the Common Anode (CA) and Common Cathode (CC).
segemen seven controllers can be done directly, or through a pattern such as a driver IC 74LS47 to seven segment CA and 74LS48 to seven segment CC.
To save power it is, the LED does not continuously switched on the frequency of 85Hz to 100Hz. How this can be applied to the output enable series of flow control as AC generators, either sine, square, triangle or trapesium. But rarely on the set of digital more often use the AC current wave form of a square, it This is because the series of digital only have 2 types of condition (logic 0 and logic 1) and simulate the process square wave can be easily carried out, namely the exchange of a logic 1 to logic 0 periodically at a certain frequency.