I want to use the 4 bit input of the cd4511 to display 0 through 9 on an led 7 segment display. Do I tie the LE, BL, and LT inputs to positive or ground? What are those three inputs?

 

All of your questions are answered in the official datasheet here:
www.ti.com/lit/ds/symlink/cd4511b.pdf

Look at the truth table on page 3-258 of the datasheet:

LT/ is Lamp Test which turns on all segments when it is low.
BL/ turns all segments OFF when it is low.
LE is the Latch Enable. When low, the display shows the digit corresponding to the value on the data inputs. When high, the last data is 'latched' and the display will show the last digit regardless of changes on the data lines.

Note that the pin names and bar over some of them indicate their function. LT means Lamp Test and the 'bar' i.e. LT/ means that the function is active when the pin is a logic low. So LT/ turns on all segments to test when the pin is pulled low. For normal operation, the pin must be high.

Good luck!

 

Lamp Test (LT), Blanking (BL), and Latch Enable or Strobe inputs are provided to test the display, shut off or intensity-modulate it, and store or strobe a BCD code, respectively. You may want to look at this data sheet with a focus on page 3-258 which shows you the truth table for the chip.

I see JohninTX already covered it.

Ron

 

All of your questions are answered in the official datasheet here:
www.ti.com/lit/ds/symlink/cd4511b.pdf

Look at the truth table on page 3-258 of the datasheet:

LT/ is Lamp Test which turns on all segments when it is low.
BL/ turns all segments OFF when it is low.
LE is the Latch Enable. When low, the display shows the digit corresponding to the value on the data inputs. When high, the last data is 'latched' and the display will show the last digit regardless of changes on the data lines.

Note that the pin names and bar over some of them indicate their function. LT means Lamp Test and the 'bar' i.e. LT/ means that the function is active when the pin is a logic low. So LT/ turns on all segments to test when the pin is pulled low. For normal operation, the pin must be high.

Good luck!

So for basic operation LT must be high, BL must be high and LE must be low.

 

So for basic operation LT must be high, BL must be high and LE must be low.

Yes. If LE is high it will ignore further changes on the data inputs and hold the last digit displayed.

 

So for basic operation LT must be high, BL must be high and LE must be low.

Yes.