I want to use only one supply at place of two different supplies, one for atmega328p(5V) and one for relays(7V). Please provide me a solution for this, I think LM7805 and few capacitors may help in this, but I am not sure. Please check the circuit diagram I have attached below.
Your picture shows two 5V power sources. Plus from one goes to the transistors. Plus from the other goes to the Arduino, but it isn't clear where it goes. If the plus line feeds into the barrel jack, the voltage is too low. The voltage needs to be at least 7V, which happens to match what you say you want to use.
Oh ya its my fault... Actually I am using standalone atmega328p which wants 5V input. I made that according to tutorial given on arduino website and it is working just fine.
Also the relays I had used are of 5V. In the beginning I was using a 5V supply only for relays but from that all the three relays were not triggered at same time. Then I got to know that the voltage gets divided and on turning all the relays, each relay doesn't get the voltage which is necessary for them to work. That's why I had used a supply more than 5 volts.
Then I got to know that the voltage gets divided and on turning all the relays, each relay doesn't get the voltage which is necessary for them to work. That's why I had used a supply more than 5 volts.
The voltage drop happens when the power supply is not capable of supply the needed current. Boosting the voltage is the wrong solution. Boosting the current is the correct solution.
If your car headlights dim when you start the car, replacing the 12V battery with a 24V battery is NOT the answer.
Thanks paul... I was using a mobile phone charger previously i.e. 5V with low current ratings, so at least how much current i need in order to make them work correctly?
One more thing, on using same 5V supply too for atmega and relay board it resets the atmega automatically... That is why I was using two different 5V supplies... Any solution for this?