7 segment LCD display question

[nebisman]

I have a LCD display for sevelar 7 segment digits, it's like a display of a clock.

My question is :

How can I identify the pins corresponding to any digit, any segment?. When I try to apply voltaje to any pins several of them are activated. How can I apply a signal for identify one of this segments?

thanks

nebisman

 

[sc/mp]

Hi

To have 1 segment ON you must apply AC (no DC !!) between Backplane and the selected segment.

So apply AC (5V RMS for instance) between to pins until you find BackPlane.
Then find each segment.

Here you have many pdf for standard numeric LCD :

h**p://www.orientdisplay.com/standard-lcd-panels.html

Good luck !

 

[mr_ghz]

Hi nebisman,

Driving an LCD is not as simple as driving an LED! LCD's has to be driven
by an AC-voltage or they will be destroyed after a while.
The connection of an LCD is often multiplexed. One pin goes to more than
one segment and you have several 'common' pins that will chose the
correct one. One possibility is that one pin drives all 'a' segments, and
there exist for every digit one common-line. To drive this segment you
have to apply a AC-voltage to the common pin and the inverse signal
(180 degree) to the segment pin.
I think it's easier if you use an LCD driver IC.

Bye

 

[nebisman]

thanks friends

which the typical AC frecuency for these devices?

nebisman

 

[techie]

Generally LCDs are operated at about 30Hz