servo and dc motor supply

I finished building an Arduino on PCB and it’s working properly…I will be adding an H bridge to control 2 dc motors and 2 servos…my question is about power supply…is the on board 5v regulator (LM7805) enough or I have to add another

maged_alex: I finished building an Arduino on PCB and it's working properly...I will be adding an H bridge to control 2 dc motors and 2 servos...my question is about power supply...is the on board 5v regulator (LM7805) enough or I have to add another

No. Absolutely.

You shouldn't ever run motors and servo's off a logic supply - logic chips need clean stable power, motors can put spikes and drop-outs on the supply. You also need far more current for motors and servos. You would normally route power straight to the motors from their supply, not waste power in a regulator.

MarkT:
You shouldn’t ever run motors and servo’s off a logic supply - logic chips need clean stable power,
motors can put spikes and drop-outs on the supply. You also need far more current for motors and
servos. You would normally route power straight to the motors from their supply, not waste power
in a regulator.

A 9v wall adaptor for example?? it’s the source I’m using to power the ATmega chip

What are the stall currents of your motors and servo? Will this power supply handle all of this comfortably without drop-outs?

A 9v wall adaptor for example?? it's the source I'm using to power the ATmega chip

If the wall adapter has low current output and both the arduino and motors are powered from it. then the motor current requirements may still pull the adapter out so low to cause the arduino to have low voltage issues. You might consider UBEC voltage regulators for the motors/servos.

http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=UBEC&_sop=15

maged_alex:
A 9v wall adaptor for example?? it’s the source I’m using to power the ATmega chip

Oh come on!

Wall adaptors have specifications in addition to “9 V”.

So do motors.

So - what are the complete specifications of each part to which you refer? Show Web links and/ or pictures.

I think a 5v3a regulator will solve the problem http://www.eleccircuit.com/5v-3a-switching-power-supply-by-lm2576/

maged_alex: I think a 5v3a regulator will solve the problem

You can only think that if you did some sums....

Servos use about 1A each so if they move together, there's 2A.

You need to know the DC motors' stall current: do you have a data sheet? If not measure the resistance and I=V/R or measure the current while you stall the motor by hand... unless it rips your fingers off first ;)

JimboZA: You can only think that if you did some sums....

Servos use about 1A each so if they move together, there's 2A.

You need to know the DC motors' stall current: do you have a data sheet? If not measure the resistance and I=V/R or measure the current while you stall the motor by hand... unless it rips your fingers off first ;)

I did the sums already ..3 a is the current I need