Confusion in power supply circuit

Discussion in 'General Electronics Chat' started by ect_09, Jul 12, 2014.

  1. ect_09

    Thread Starter Member

    May 6, 2012
    please tell me that how much will have this power supply.
    because its mentioning the voltage and but not current,

    it can produce 1A current.???
    kindly guide me in this way.
  2. studiot

    AAC Fanatic!

    Nov 9, 2007
    Considering the size of the reservoir capacitor and the fact that the regulator IC is labelled simply 7805, I would expect it to be able to source up to 1 amp.

    Note I say 'up to' because the regulator sets the voltage, not the current.
    The current is set or drawn by the load. A heavier load with lower resistance will draw more current from a 5 volt supply.

    With the 12 volt AC supply from the transformer the regulator will be dissipating around 15 watts at 1 amp so will need to be on a substantial heatsink.
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
    A 6 or 9 volt transformer will lower the power dissipation of the voltage regulator.

    the weakest link in thus supply will be either
    - an overheating regulator (it will shutdown automatically if overheated)
    - transformer current (VA rating) is too small. ( make sure your output is at least 1.5 or 2 Amps (18-24 VA or more for 12 volt)