AboZakaria

hi all
I have seen this Cicuits(A 30 A Power Supply) and i wonder if its realy works and if its works can we replace the transistors(witch only pass current) with only a thick wire

http://www.zen22142.zen.co.uk/Circui...er/1230psu.htm

mvs sarma

A relay will shrot circuit the Regulator IC.
Imagine 29.5 amps passing thro' a resistor( assuming the contact works like a resistor) across the 7805. if the contact resistance is taken as 0.1 ohm, there is a 3V drop across it. and burns around 90watts (29.5*29.5*0.1) at the contact point itself and the contact gives you a beautiful fireball.

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Regards,
Sarma.

audioguru

The TIP2055 power transistors continuously adjust their conduction as controlled by the voltage regulator so that the output voltage remains at 12V when the load current changes.

The voltage regulator cannot control the amount of conduction of a piece of wire.

Many power transistors are used to share the current and to share the heat.

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Uncle $crooge

AboZakaria

thanks alot

IQBALSOUND

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audioguru

It is a stupid circuit:
1) Its transformer's voltage is way too high.
2) The regulator has hardly any current (it won't give up unless it doesn't have a heatsink then it shuts down when it gets too hot).

At 5A each, the power transistors will have a base-emitter voltage of about 1.3V and the 0.1 ohm emitter resistors will have about 0.5V. Then the 100 ohm resistor and the regulator will have a current of about 18mA.

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Uncle $crooge

scientist36

that circuit is failure,try to change conect basis of transistor to the output of 7812 and add capasitor to ground,the collector of transistor conect to input of 7812 and then emitor as output the psu with adding a capasitor,try with 6 or more npn 2N 3055 transistor paralel to make high current,that will work,

bryan1

As the OP showed in his schematic is a mains input WHAT DOES THIS HAVE WITH ALTERNATE ENERGY.


THIS BELONGS IN THE TRASH

sworry for shouting but my point remains

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" The only way to avoid human error is to avoid the use of humans"