[SOLVED] Problem with low current of 7805 regulator

[anonymous.]

I used the 7805 regulator recently with an AVR and LCD.
it did not deliver the needed power and the circuit did not work correctly(at least the LCD). I had to use power from usb.

the only reason i could think of was that the delivered current was low, although its rated for 1A in the datasheet
so why is that ??? and how can i get high currents from the regulator ??

 

[srizbf]

Re: 7805 current problem

one reason is , 7805 that you have got may not be rated for 1Amp.
if it is a TO-202 package then it can.

other reason , if you have TO-202 package and not getting 1amp is dueto:
--- because of (Vin-Vout) in 7805.
probably you would have used a 12v dc with 7805 to get 5v.
try to reduce the Vi to say 9v and see the output.

 

[anonymous.]

Re: 7805 current problem

I am using a TO-220 package with a 9v battery .

 

[dselec]

Re: 7805 current problem

9v battery ???? conventional 9v batt can not supply 1 amp

 

[srizbf]

Re: 7805 current problem

then it is not a 7805 problem. it is the 9v battery.
the 9v battery , that we get nowdays are fareastern origin and drains very quickly even for low current loads.
substitute a new 9v battery and see.
or have a regulated power supply.

 

[anonymous.]

Re: 7805 current problem

ooops.

how did i miss this !!!
thanks guys !!

 

[dselec]

Re: 7805 current problem

a new batt will drain quick so use 2-3 rechargeable batts in parallel blank out lcd when not needed