Which is better Configuration for Power Supply ?

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Which is better Transistor Configuration for Power Supply ?

Hello,

I have shown the image with two different configuration... Please guide me which would be better combination ? Is there any chance of reducing heat by changing configuration ? As Collector region is bigger than emitter so which of the design is better ? Does it matter ? which design i should consider or both of them are same ? M little bit confused...


 

With the first circuit, there will be .8V dropped across transistor, in the second, .2V. You notice this by the slightly lower current in the first figure. The second figure will have 1/4 of the dissipation of the First ( 1 = 2 A X.8V = 1.6W, 2 = 2A X .2V = .4W).
Frank
 


Thanks mate....for your information...

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So 1st figure is common emitter configuration and 2nd figure is common collector circuit right ?
 

So 1st figure is common emitter configuration and 2nd figure is common collector circuit right ?
Click to expand...
No actually reverse is true.

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I think first circuit is better than later. In the second circuit you do not get any gain, because base current is already very high ~2A (~loss), while first circuit carries only collector current and base current is minimum.
First circuit shall dissipate less power.
 

Re: Which is better Transistor Configuration for Power Supply ?

the second one designe is suitable and 99.9% designer use it .
in second designe transistor is using as switch.








i sugess you that if you are going to use transistor as switch and controlling larg current then EMOSFET is best choice.
 

ohh k guy....can anyone tell me how much minimum current i should provide to transistor base for its full conduction state... i mean fully on.... ? which factor i should look into datasheet ?
 

Find out the BETA of the transistor from spec, Find the wattage of the bulb (decide how much current you want in bulb).
Ib=Ic/BETA. YOu know the base current, decide the base resistance accordingly.
 

ok thanks...will calculate it...

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But do you think....applying excess current to base can also be factor for more heat produced ?
 

There is maybe also a safety aspect to consider as well. The high side switch is prefered because in case of a failure (e.g. the 24V wire breaks or is shorted to ground) it will most likely damage the driving transistor, but not the total 24V power supply.

Enjoy your design work!
 

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