Technology Everysecond » cathode http://mnunioni.org seabloggers INC Fri, 03 Sep 2010 03:41:58 +0000 en hourly 1 Display Interfacing http://mnunioni.org/2009/06/04/display-interfacing/ http://mnunioni.org/2009/06/04/display-interfacing/#comments Thu, 04 Jun 2009 11:27:04 +0000 admin http://mnunioni.org/?p=111 Most of the microprocessor controlled instruments and machines need to display letters of the alphabet and numbers to give directions or data values to users. This information can be displayed using CRT , LED or LCD displays. CRT displays are used when a large amount of data is to be displayed. In systems where only a small amount of data is to be displayed.

Interfacing Static LED Display

Consider a circuit for driving single seven segment LED display. For common anode, when anode is connected to positve supply, a low voltage is applied to a cathode to turn it on. Here, BCD to seven segment decoder, IC 7447 is used to apply low voltages at cathodes according to BCD input applied to 7447. To limit the current through  LED segments resistors are connected in series with the segments. This circuit connection is preferred to as a static display because current is being  passed through the display at all times.

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