Can we convert 24 volt DC to 5 VDC with use of 7805?
is it need any capacitor in input?

 

What current, if reasonably low it can be done with zener, resistor and cap.
Max.

 

Yes you can easily. What's your load amp draw though?

 

Hello,

It is possible, but you will loose a lot of power in the regulator.
The heat generated in the regulator will be (Vin - Vout) * Iload.
In your case almost 80% of the input power will be transferred into heat.

Bertus

 

Maybe an efficient, off-the-shelf 5v switching regulator like:http://www.ebay.com/itm/3-Terminal-5V-1A-Switching-Voltage-Regulator-Power-Supply-/261243604047

Ken

 

Switching is better for this big a drop. A dropping resistor can decrease the heat in a linear regulator, but does not improve the overall efficiency.

 

If say it was only 50ma this would only need a 1watt resistor together with a zener.
Very simple.
Max.