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Help with 7 segment display

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lefam

New Member
Hi guys.

I have bought some 7 segment LED displays (common anode). But the pins are not arranged like in 7 segment display below.



My displays have the pins in the left and right side (instead of in the top and bottom like in picture above).

Can you help me using these displays.

In the website I bought them they had this diagram:


Please help me to use these displays.
 

crutschow

Well-Known Member
Most Helpful Member
Deleted incorrect answer.
 
Last edited:

RODALCO

Well-Known Member
You need to experiment here a little bit.
Use a 5 Volts supply and put a resitor in series with one of the test leads (470 ohms) to limit the current to about 10 mA.

It looks that PIN 1 left bottom row is the CA terminal

Attach the positive lead to one terminal to start with, then with the other lead touch the other terminals one at the time.
Repeat this for all pins.

You will find that with the correct pin at positive voltage, all the other segments and the dot will light up when the terminals are touched.
That is the common anode ( CA ) terminal of the display.

As this is a common anode display a 7447 driver can be used.
 
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lefam

New Member
I figured out which PIN is the common anode with a procedure similar to the one proposed by RODALCO. The upper left PIN and bottom right PIN are common anode terminals. The diagram seems not to be correct. I think it is for a different model of displays.
Thank you
 

crutschow

Well-Known Member
Most Helpful Member
Sorry, I misread your question.

You should be easily able to determine the pin order by experiment as Rodalco suggested.
 

stephen87

New Member
To check the proper pins i suggest that you grap 1 seven segment and then test it with the a digitial multimeter with continuity test. If the red probe is connected with tha anode and the black probe is connected to the cathode, one of the led's will be lit on. From there you continue doing that and will extract the circuit diagram yourslf since you have got any idea of the pins.
 

lefam

New Member
Problem solved.

To check the proper pins i suggest that you grap 1 seven segment and then test it with the a digitial multimeter with continuity test. If the red probe is connected with tha anode and the black probe is connected to the cathode, one of the led's will be lit on. From there you continue doing that and will extract the circuit diagram yourslf since you have got any idea of the pins.
I think this approach is easier and more safe. Thank you.
 

crutschow

Well-Known Member
Most Helpful Member
To check the proper pins i suggest that you grap 1 seven segment and then test it with the a digitial multimeter with continuity test. If the red probe is connected with tha anode and the black probe is connected to the cathode, one of the led's will be lit on. From there you continue doing that and will extract the circuit diagram yourslf since you have got any idea of the pins.
The continuity test voltage of a digital multimeter may not be high enough to light the LEDs.
 

superflux

New Member
You might also want to be aware that depending on the size of the 7 segment, some of them have 2 LEDs in series or parallel per segment and usually just one LED for the decimal (DP).
 

ash20

New Member
you can see the model number for the display and see the datasheet for it... it will tell everything about pins and voltage it needs...
 

superflux

New Member
you can see the model number for the display and see the datasheet for it... it will tell everything about pins and voltage it needs...
A lot of these 7 segment displays come from china and the datasheet rarely matches what is inside the display. Buying from Kingbright will probably be the best way to get something that matches the datasheet.
 

stephen87

New Member
With continuity test the meter outputs a voltage of about 1 to 1.4v and this will be enough to lit the LED. with the diode test i think it will be the same voltage output.
 

blowouter

New Member
Mine

Once i have 1" common anode 7 segment i try continuity test to find pins but it didn't work at all
can diode test do that?
 

ChrisP58

Well-Known Member
Once i have 1" common anode 7 segment i try continuity test to find pins but it didn't work at all
can diode test do that?
The diode test function of most multimeters should work. And, in my experience, will light up the segment being tested when forward biased.

Of course, the best way to know what pin drives what segment, is to check the datasheet. :)
 
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