Need help with 7 Segment LED , how it works

I have a 7 segment LED. Its model number is LTS 3731E. The datasheet is located at :

LTS3731E datasheet and Application Note, Data Sheet, Circuit, PDF, Pinout | Datasheet Archive

I used the first data sheet, it has the pictures of the diagram of the 7 Segment LED

What i plan to do , is use a 74LS47 to turn on the 7 segment LED. What i dont get is the pin assignment. I have 5 pints on each side. How do i know which is first pin, and which is which.

Also, if i understand right, for it to work, the anode side is connected to a single point. That point is connected to voltage. When the cathode is 0, or like ground, it will light the led up . correct ?

Also what does a cathode L.D.P and CATHODE R.D.P mean ?

Just like with any LED, you need to place a current limiting resistor in-series with each cathode to limit the current less than 20mA.
LDP and RDP refers to the Decimal Point Anodes.

Yes i understand I must place resistors, this i know. But, how do i know how pin arrangement goes. Which is first, and so on . Then how does it loop to other side, to know which pin # is what

Looking at the top, the pins are numbered counter-clockwise, just like any Dual-Inline IC package. The data sheet shows an X for pin 1. It is not clear if that mark is embossed in the plastic, or what?

I suspect the "X" on the drawing is there to show the position of pin #1. I doubt there is an actual "X" on the device.

As pointed out the pin layout is the same as a standard 14 pin IC.
To find the bottom of the LED, hold the LED at different angles while viewing the front of the LED, the decimal points will be just visible, they are at the bottom of the LED.

EDIT:
If you are unable to see the DP, use a 330R with a 5V power supply.
By connected one pin to 0V and any other pin to +5V via the 330R, one segment should light, if not reverse the 0V and resistor pins.

Work your way thru the pins, in a few minutes is easy to work out which pin is which.

do i connect both pin 3 , and 14 to +5 volts, or just 1 is sufficient ?

integralx2 said:

do i connect both pin 3 , and 14 to +5 volts, or just 1 is sufficient ?

Click to expand...

You should not connect pin 1 to +5 volts as it is Cathode A.
Pin 3 and 14 are internally connected so you may use either or both of them for +5 volts.