help with a circuit for a high voltage/current 7-segment display

kingspud

Hello everyone,

I am using a BS2 to run two 4511 binary-to-digital converter chip to display numbers up to 99 on a high voltage/current dual 7-segment display board.

The problem is the display only works with voltages higher than 9 volts and the 4511 can only push 5 volts and low current.

Does anyone out there know the best way to use transisters in this circuit so:

1.· I can get the transistor circuit to trigger off the 0 to 5 volts without·burning up the 4511 chip or my BS2 chip in the process!!!!

A circuit diagram would be helpful if you already have one or can put one together.

I have tried this circuit with the NPN transisters but I ended up frying the 4511 chip and luckily didn't get my BS2 chip.

Thanks for any help!!

Joe

Mike Green

The NPN transistor circuits shown in the "Industrial Control" tutorial from the Parallax website should work (Support / Downloads / Stamps in Class Downloads) as long as your display requires a common-anode display. The 4511 puts out a logic high for segments to be turned on which is perfect to drive a NPN transistors which will connect their output to ground. If that's not what you need, you have to use the NPN transistors as inverters and have PNP transistors to actually switch the displays.

Without more information from you about your display, it's impossible to provide a circuit diagram or anything more detailed since you've left so much unspecified.

PJAllen

http://forums.parallax.com/showthread.php?p=705997

kingspud

Thank Mike,

The display is a [noparse][[/noparse]4] segment display from Maxx Tronic MX006-1 led display

MX034: SEVEN SEGMENT DISPLAY 3” (Standard·LEDs)

Detail:
-Display dimensions : 46x75 mm. or 1.78x3 inch.
-PCB dimensions : 63x85 mm. or 2.5x3.3 inch.
-Power supply : 12 Vdc.
-Display used : Ultra-bright LEDs.
-Consist : 5 LED’s per segment and a LED’s for the decimal point (p).
-At 12Vdc. A segment current ~ 15 mA.
15mA.»A decimal point (p) current ~
Total current ~ 120mA.
Fully Assembled and Tested

kingspud

also, thank you PJ Allen, I will take a look at what you guys gave me...

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
“Intellectual growth should commence at birth and cease only at death”
Albert Einstein