above the diagram the COM has 3.2V output. If that volts is enough for mosfet, I would like to use it. Please can i have how the mosfet work and how to put between circuit?

 

yes sir! I have that circuit.

 

above the diagram the COM has 3.2V output. If that volts is enough for mosfet, I would like to use it. Please can i have how the mosfet work and how to put between circuit?

I need to know the specifications of the 2.3" displays that you want to use...

B. Morse

 

I do not know whether is correct or not. I found on led is


PA6 WLG
D23012A/B(E)

 

read this to learn how to use a mosfet as a switch, since you can not provide any details or specs for the displays you have... http://www.electronics-tutorials.ws/transistor/tran_7.html

Good luck...

B. Morse

 

Size: 2.3'' (69.70mm*47.80mm*12mm)
Forward Voltage: 7.5V
Forward Current: 5-10mA

This is i found on google. But I couldn't find data sheet for that LED.

 

this is the nearest one I found on net.

 

Forward voltage 7.5 volts??

Are you sure?

 

i guess. I try with 9v supply and 1K Resistor

 

I go to net and I just get that info. Only
another type is 8Volts.

 

Must be three LEDs in series. It's odd, because I've never seen that in LED displays, though I suppose yours is quite tall so that might be why.

You might as well run the logic circuitry off a +7.5 volt supply. If it has 4000 series ICs this is not a problem. If you have 74xx ICs it could be an issue.

Which circuit are you using?

 

Hello,

There are large displays with upto 4 leds per segment (use the correct current limiting resistor per segment).
These can be driven using an 74LS47 , wich has open collector outputs that can handle upto 15 volts.

Bertus

 

Thank you! I'll check it out!

 

My IC no. is MDT 2005EP 6432JG

 

Right now I am using this circuit. By the way please can you provide fully instruction. Like Diagram for whole things. because I am really new in this. Thank for your effort.

 

I have CD 4026B too. But I do not have the circuit to built. And I do not know it is for common anode or cathode. Please Advice! Thanks!

 

You sent me this PM:

I change all a,b,c,d,e,f,g out put resistors to 1K. Then I supply voltage 6V~9V to com. the first digit work. about 15minutes my IC fried.
anyway thank you for your helps!

That's using a PIC microcontroller. No PIC can take 9 volts for any extended period of time. 7 volts is the absolute maximum.

I suggest you use a CD4026B. These have a 7 segment output. Each IC has a /10 output. This basically counts 10x slower than the input. You can feed the /10 output to the next IC's clock input. You can repeat this chain to have 4 digits, counting from 0000 to 9999.

These circuits only work with common cathode displays. If you can't get common cathode, you need to have open collector outputs, which increases the complexity (more chips).

 

Yes Sir, I am trying now. And out put current is 4.9V with 9V supply. If the thing can settle I'll let you know.

 

Well, if people would look at what the OP has posted as a circuit that he is using maybe he would not have been led to burnout his uC....

The Circuit he WAS using was for common anode displays, he would have just had to add a transistor to switch the anode side to handle the current, then the transistors could have been just powered off of the 9 volt supply.....

But when people just start chiming in without a clue, this is what happens...

B. Morse

 

Most counter circuits use the common cathode just like this one which is easily expanded to four or more digits.....

the 4511 can be swapped out for the 74LS47 so it will work with common anode displays....


B. Morse