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| Feedback on power supply 0-30V 0-4A |
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| d4n13l:
Hi, I'm working on my first power supply 0-30V 0-4A, and I'd appreciate some feedback, specially in two points: 1) Right now the slightest turn of the potentiometer VR1 allows for a lot of current, I'd like to make it more sensible, but I'm not having much luck 2) I want to add a voltage/current meter, I tried a L7805 connected to the second transformer to feed 5V to the meter but the moment I connect the terminals to the output I get an extra volts in the output instead of zero, not sure why. Also I'd appreciate any comments on the design. Thanks |
| Circlotron:
IC1B is operating with far too much gain. Put a resistor say 1K from pin 6 to ground and 100nF from pin 7 to pin 6. These values are just starting points and may be way away from optimum. This will roll of the high frequency response of the op amp and hopefully make it more stable. It is most probably oscillating like crazy. |
| d4n13l:
Hi, I tried a bunch of resistors values and didn't see any aparent effects on the behaviour. Same for the capacitor. |
| xavier60:
--- Quote from: d4n13l on July 27, 2019, 04:18:12 am ---Hi, I'm working on my first power supply 0-30V 0-4A, and I'd appreciate some feedback, specially in two points: 1) Right now the slightest turn of the potentiometer VR1 allows for a lot of current, I'd like to make it more sensible, but I'm not having much luck 2) I want to add a voltage/current meter, I tried a L7805 connected to the second transformer to feed 5V to the meter but the moment I connect the terminals to the output I get an extra volts in the output instead of zero, not sure why. Also I'd appreciate any comments on the design. Thanks --- End quote --- How does the voltage regulation work? |
| d4n13l:
It works as supposed to, 0-25V with current resistor values. I think current regulation is working also, just as I mentioned very light changes in the potentioner go from 0 to too much since ground is receiving about 0.9V/0.22ohms allows about 4A. Which is a wide range to cover. |
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