sevent segment drive problemo

Hi guys..

I'm designing a safety deposit box with 6 seven segment as display..

I drive the seven segments using pnp transistor.. but the 7805 become very hot when the seven segments are ON..

can I use the 12v power supply to supply the seven segments?
what should I use

can someone help me?

Use 220Ohm current limit resistors in led common line
will fix your problem

mk

It's a wonder you're not destroying your display. Put a 120 ohm resistor in each of the seven segment lines (not in each of the six common lines). Of course, only turn on one transistor at a time. The 7805 will still dissipate 1 watt maximum, so if it still gets hot, you should get a bigger package style, and/or heatsink it.