Hello Friends,
i have made an project to dislay the time on 2*16 LCD with pic 16f877a.it is working fine with 12v dc adapter(input ac 230v) which is converted into dc by LM7805 and a .01uf capacitor. it is working fine and LM7805 is also normal.
Now i am planning to place this unit in car. so to power up this board shall i connect the car battery mains(which is also 12v) directly to the unit or shall i need to build any precaution circuit for it.
Please guide me..
You may power it up directly, but you may add this to isolate the microcontroller circuit from the +12V line and other circuitry/devices running off it. It will be better.
Yes, 7805 is okay. You should use a heatsink, the size of which will depend on the current. If current is <200mA, however, you may not need to use a heatsink. However, it is still good practice to use a small heatsink.