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singonn2

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  1. hi everyone , now i doing new 5A power supply project using schematics and part list provide by redwire in first page . now i meet a problem , the LED is light while i switch on power same as noworries , i still using 24VAC 3A transformer for a test before get a new 30VAC 5A transformer. When i using TLE2141CP OPA U2 was heat up very fast , U2 pin4 was 2V ,i had already take off Q4,Q5 . Negative supply for U3 pin4 is -1.5V , U3 pin7 voltage is about 20V. U1,U2 pin7 is 31V it's normal , but pin4 only a few mV. Any pro can help me ? thx. :)
  2. isn't the display voltage unstable because the resistor 5%-1% relation?any pro answer it ?
  3. guru isn't i can connect the fan cooler to the line about 3xV after bridge rectifier and add a resistor for reduce the voltage to the fan. half-wave rectification ripple is too high, i hope the fan wont easy mangle, for economize diode and circuit can just borrow the current from bridge rectifier? isn't in theory full-wave rectification ripple algorithm same with bridge rectification ?
  4. thx for guide guru, the transformer i already series for gain 24VAC isn't i can pull one more line from one of 12VAC with a diode mean half-wave rectification = about 6VAC? the return circuit of the fan is point to the return circuit of transformer?because when i series the transformer 12V+12V the return circuit is doesn't use. sorry guru i don understand how filter the rectified 12V to 16V use other rectification way? any diode also ok ? or at least 3A diode
  5. guru my transformer is 12+12V=24V ,after bridge rectifier is about 36V actually need how much input voltage for LM317HV to gain 12V with about 0.5A and the watt is lowest. isn't LM317 input about 12-13V output will 12to13V also?
  6. thx guru.Both method need a heatsink again :-\ now my problem also hard to get a pretty big heatsink , heatsink is also quite exp , LM317HV 12V with mA also will very hot?can i just put it circuit on a perfboard and cooling with fan cooler also?the input of LM317 can i just borrow the current from bridge rectifier ?
  7. sorry , i mean i hope add a fan cooler for the ps with using the voltage and current from U1 output isn't okay?or other ideas without using 2 power supply for the fan cooler, because my heat sink quite small so i add a fan cooler.
  8. i think need make a FAQ about this power supply project because it's a lot newbie doing it. guru can i put a cooler on U1 output ? or other ways without using 2 power supply for add the cooler.
  9. ya,one of it,after i replace U2 with TL081 the voltage is like my notion as u say higher voltage than output voltage,isn't TL081 can replace with TL082 ?sry for my bad english. the LED is always light up now i see , i had put the Q4 on a heatsink + a fan on it , 26W wont reach 200*C is enough. the cement resistor i use is heat up very much although not more than 5W. thx for your guide guru.
  10. thx guru the fringe problem is fix reason was a ic741 was burned , from original circuit U3 output voltage is about 30VDC and U2 output voltage along with the supply voltage change isn't correct? the ripple can check with electric meter ? if the digital electric meter show the voltage is fix at 0.01xVDC mean low ripple ? this circuit have auto protect function ? mean when the output voltage is short circuit will have a signal ?what the function of D12 LED ? when it will light up ? when i supply to 20VDC + 2A the Q4 2N3055 is heat up too much can i use 2x 2N3055 like the new circuit for relief it heat up ? and the R7 also heat up quickly should i change to it 10W resistor ?
  11. i using 24VAC with 3A isn't can replace TL081with741? , the led is no light up , isn't the leb light up while DC output short circuit ? the C1 voltage is 33VDC the output of U1 is 11VDC and the -5.6V voltage there is -5.6VDC also it's correct?the point i check the voltage of -5.6V is between R3 , D7,U3/U2 -V there. U1/2/3 and +V there is 33VDC mean after bridge rectifier is 33VDC and the R1 and R2 (1W) resistor will start heat up quickly but Q4Q1 seen not working cos did't heat what problem is it :(
  12. can someone post the full different effect btw the old version 0-30V Stabilized Power Supply with current control and the new updated version? please replace the older version if it's unsafe or too much bugs cos it really make newbie lik me confuse :-[ isn't the older version totally unable to use ? or it's just will heat up/more ripper when supply up to 20VDC ? can also provide a most accurate mod parts list ? thx sorry for my broken english
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