Whats the role of 2 transistors in this power supply?

[borut]

Power supply problem?

Hello,

please give me some information about the attached power supply? I don`t understand the exact role of the two transistors (BD176 and TIP32C)? I even don`t know what is the output voltage (Uizh = ? V), is 4V? I will be very thankful if somebody will explain me the function of each particular element?

Thank you in advance!

Bye bye

 

[sztibi82]

Re: Power supply problem?

the 7808 is a 8V power supply.
The idea witht the BD176 and TIP32C is that, if a short circuit occurs, the IC is protected. Also the BD and TIP has to be there to increase the power so the IC is about a few mA but using that transistor combination it can be about2-3A.


If any more questions just post

 

[afonso]

Re: Power supply problem?

Hello,

please give me some information about the attached power supply? I don`t understand the exact role of the two transistors (BD176 and TIP32C)? I even don`t know what is the output voltage (Uizh = ? V), is 4V? I will be very thankful if somebody will explain me the function of each particular element?

Thank you in advance!

Bye bye

The tip32c acts as a boost of current, and the BD176 as a over current protection. The output voltage will be 4 V without load.


By the way, there is a mistake in your schematic. The BD176 is a PNP transistor, not a NPN.

 

[E-design]

Re: Power supply problem?

More than one mistake, the output current is drawn via the 220Ohm resistor? Why then do you need the current boosters in the first place?? Output voltage will drop depending on the amount of current drawn. Is this a voltage regulator?? :?

 

[cetc1525]

Power supply problem?

I think it can work positive or negative?

 

[borut]

Re: Power supply problem?

Thank Yoo for the help.

 

[Borber]

Re: Power supply problem?

Your schematics is standard current boosting circuit with current limiter arround 7808. The real output of this regulator should be at pin 3 of 7808 if you want some output current and voltage is 8V as you allready know.