Likely something else.the constant current its not working, is that beacose i didnt put the pnp transistor bc557 or something else
Do you mean that you didn't fit a transistor in the position for a PNP?is that beacose i didnt put the pnp transistor bc557
I used 0R33 ohms just like in the schematic but i want the current to be adjustable from the minimum it can go to the maximum it can goLikely something else.
What's the purpose of T1?
The limit takes effect when the voltage from CL to CS created by the T3 emitter shunt resistor (can't make out its reference no.) due to the output current equals about 0.65V.
What's the value that you used for that resistor?
What current limit do you want?
Yes i get varible voltage by turning the potDo you mean that you didn't fit a transistor in the position for a PNP?
When you say it isn't working do you get voltage but there is no limit on the current?
Yes i get varible voltage when im turning the 10 k pot but when i turn the 1k pot doesnt work for the current limitingDo you mean that you didn't fit a transistor in the position for a PNP?
When you say it isn't working do you get voltage but there is no limit on the current?
That pot, as configured, will have little effect on the value of the limit, as you have found.I used 0R33 ohms just like in the schematic but i want the current to be adjustable from the minimum it can go to the maximum it can go
I used a smps 20v 5AThat pot, as configured, will have little effect on the value of the limit, as you have found.
0.33 ohms will give a limit of about 2A.
What current limit range would you like?
What is the voltage and current rating of the transformer you used?
Even with a modified circuit, the current limit would have a limited range of adjustment, unless you significantly modify the circuit, such as with an added op amp.
Okay thanks today when i come from school i will try that and i will give feedback about how it wasWhy did you not add the transistor etc?
That circuitry around T1 creates a constant current source and so will develop a voltage across P3 to set the current.
Build the circuit as shown and see if it works.
Ah, thanks for that.That circuitry around T1 creates a constant current source and so will develop a voltage across P3 to set the current.
It's the 0.33 ohm T3 emitter resistor which generates a voltage sensed by inputs CL and CS.I don't see how the current limit in the new circuit works. There is nothing to actually sense the output current.
No.
I meant in the new circuit - so we agree!It's the 0.33 ohm T3 emitter resistor which generates a voltage sensed by inputs CL and CS.
Sorry, I missed the "new" in your post.I meant in the new circuit - so we agree!
by Aaron Carman
by Jake Hertz