lm317 cant changing adjust pin voltage

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Note that the current limit will not work when the output gets below 1.25V (e.g. a short).
 
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alec_t said:
Try this simplified arrangement :-
View attachment 124263
Click to expand...
Working.. Also in simulation , also in appliance. Many Thanks.
But another problem is voltage drop of output. For example oıtput without load there is 24v. On 33ohm load , it drops to 14 v. I know this happens because of the no feedback. Although i change control voltage , output cant move back to 24v. Only goes about 20v.
What can i do for that issue ?
 
Did you measure the regulator input voltage when the load was 33 Ohms?
Is your circuit built on a breadboard?
 
alec_t said:
Did you measure the regulator input voltage when the load was 33 Ohms?
Is your circuit built on a breadboard?
Click to expand...
Yeah your right. Input is fallin about 25v. so 22-23v output becomes normal. I didnt notice input is falling ! It musnt be fall like that. Because i have 20,5v 11amps transformer. Huge transformer. Shouldnt expect voltage drop on input cause of that huge transformer.

And yes im currently tring on breadboard. First circuit was on printed board.
 
qwertyqwq said:
Transformer is like that one. Seperated two 115v primar winding. Out is 20,5v 11amps.
Click to expand...
?? The transformer in the link has a 30V output rating.
A 20V transformer has a peak ouput voltage of 20*1.414 = 28V. A bridge rectifier will reduce that to about 26V under load.
Breadboards are not designed to handle high currents and their contact strips do not provide reliable connections. Some voltage drop might be experienced there.
 
alec_t said:
The transformer in the link has a 30V output rating.
Click to expand...
Yup i know. Caıse of that i said that;sorry couldnt find my transformer on internet.
qwertyqwq said:
Transformer is like that one.
Click to expand...
alec_t said:
A bridge rectifier will reduce that to about 26V under load.
Click to expand...

And yeah i forgot to calculate recrifier forward voltage drop.

After some arrengment i ll build circuit on printed board.

Many thanks for informations. Because of that i really love this forum. experiences talks , not assumptions. You guys doing great jobs.
 
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