The circuit Seven Segment CA

In a series of seven segment common anode (CA) to turn each segment is required logic '0 '. Thus a power supply or logic '1 'on the anode seven segment. Typically, the anode seven segment CA granted an additional one particular type PNP transistor as BC 559 or FCS 9012 to set the current flowing in the anode seven segment is not too big. In addition to the anode transistor can also function as a switch on the seven segment CA, because if given the logic '0 'on the base of the transistor then seven segments can be lit in accordance with the logic input abcdefg numbers on seven segment. For a figure that usually use IC decoder 7447 in seven segment common anode and 7448 in seven segment common cathode. So much easier to form the numbers on seven segment using 4 bit data path from 0000 to 1111 to cover all the numbers so the savings pin for data communication. There are also without using a decoder IC but still use the line 7 bits of data on each segment of abcdefg so must make manual configuration of data points.


At seven segment can be made a few digits, eg only 6 digits. So to turn seven segments simultaneously to do the scanning process for each digit seven segment. So the usefulness of transistors on the anode seven segment was very helpful to do the scanning process by switching on each digit in turn along with the turn of the seven data bits in each segment. The scanning process must be done very quickly at all digit seven segment alternately at least 60 times a second to create a seven segment as if lit simultaneously. Therefore to make a multi-digit display on seven segment must have 2 pieces of the data path to the data forming the numbers and data to transfer digits. To save some data lines that combine into 1 piece of 8-bit data path by adding the line demultiplexer and decoder transfer digit seven segment were combined into one 8-bit data path.

Simple application seven segment multi-digit CA to counter.