ParkingLotLust
Member
Just a quick question: will a 7805 supplied by a 12v power brick, pushing around 200mA need a heatsink, or will it stay cool? How about with something like... 7.5v?
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Hero999 said:Does anyone actuallty know the thermal resistance of the TO220 without a heat sink?
I haven't seen any infromation on it.
It also can't pass 250mA.eng1 said:Is it an 78L05? Don't use it! It can't dissipate 1.4 W.
Ron H said:It also can't pass 250mA.
Hero999 said:Whilst I agree, 100mA is guaranteed and 200mA is more typical.
if u add up two 7805s and the resistors, u will be better off with a single regulator that can handle more current
Then the backlight is overloading the power supply.desperadogear said:but whenever i use switch the backlight of lcd(16x2) ON the circuit becomes very dull and the alarm seems to cry weakly..
and in another circuit where i use a 128 x 64 lcd the circuit refuses to work at all when i swithc the backlight on...