Try varying the current on pin 3 as shown in the test circuit.
omg. thank you very much.
before your reply, I tried test circuit. but it not work
(
after your reply, I try again. remove pin 1 and pin 2 --> work
Now I can control duty cycle :idea:
thank you very much!!!!!!!!!!!!!!!!!!!!!!
---------- Post added at 11:31 ---------- Previous post was at 11:21 ----------
not enough post, can't add image. Now enough
Why I use uc3842, it work but when use uc3844, haven't signal output
the circuit I remove pin1, pin 2
when V pin3>xxx --> output=0
ps: I speak English very bad
. thank for read my thread :-?