Constant current

[PRBS]

Does anyone can help me how to implement constant current on BOSOZ?🙂

 

[Freddie]

Check this out.
http://www.aussieamplifiers.com/se-sch.htm

/Freddie

 

[PRBS]

Check this out.
http://www.aussieamplifiers.com/se-sch.htm

/Freddie

Thank you Freddie. I am not familiar with active constant current. If I want to creat 40 mA constant current, how should I do?🙂

 

[Nicke]

Read this thread for info about constant current source:

http://www.diyaudio.com/forums/showthread.php?threadid=2223

And read the article about DIY opamps at (there you can find how to make constant current sources) :

http://www.passdiy.com/legacy.htm

/Nicke

 

[djk]

With reference to this figure: http://www.aussieamplifiers.com/se-sch.htm "If I want to creat 40 mA constant current, how should I do?" R8,9 cause Q3 to turn on.When the voltage across R10 reaches the base/emitter threshold voltage of Q4 the current becomes constant.Thus a beV of 0.6V divided by an R10 of 10 ohms would give 60mA.

 

[PRBS]

Thank you djk, I understood that already.

Does the gain of that circuit reflects R1+R2 divided by R3+R4?
That means, 2k ohms/440 ohms aorund 4.55. Am I right?🙂

 

[Jens]

Alternatively, use four LM317 with 30R resistors (for ~40mA) between pin Adj.(1) and Out(2), connect pin In(3) to the S of Q1/Q2 and pin Adj(1) to R17 (-V). That’s all.

Jens