30 July 2019 at 9:10 #6120
So I was right to think of oversight ,that I went crazy this morning.25 September 2019 at 17:47 #6545
E’ a problem arose, l’ atx that i can use does not have -5V, so I was thinking of a 7660a which is a dc / dc converter that with only 2 10uF capacitors I would have -5V from + 5V, it could be a problem?25 September 2019 at 20:53 #6550
It is more than good since it only serves to drive the gate of the mosfet. The current at the gate is negligible28 September 2019 at 18:04 #6575
unfortunately it does not limit the current, provided he hasn't made any mistakes.
So I mounted it on bread and used an active load as a load, set to absorb about 1A , at this point acting on the potentiometer nothing changes, that is, the load always continues to absorb 1A.
At this point I tried to measure the voltage on the pin 1 of the lm358 and mass, e và da -1.7V a +10V, according to the position of the potentiometer, all on one side or the other.
There is some evidence that I could make or change?
Thanks so much.
I made the connections all over again.28 September 2019 at 18:22 #6583
Try to see if increasing the absorbed current the output voltage drops, this circuit is essentially a constant current generator, eso lowers the output voltage when the current exceeds a certain level in order to stabilize the current.
I advise you to test with a resistance, the active load varies its characteristics to always have that circulating current and risks that the two circuits compensate each other to stabilize the current.29 September 2019 at 18:38 #6592
Tested with a resistance of 2 hom, about 2.4A of current but regulates only 0.1A.1 October 2019 at 19:38 #6598
Since it must ultimately be a constant current generator, I thought of this:
see source fidocadj Zoom fidocad
It should limit from 0.1A to about 1.5A.
The resistance should dissipate P = ( i * i ) * r = ( 1.5 * 1.5 ) * 1 = 2.25 Watt
while the transistor which has an rds 0.16 ohm P = ( 1.5 * 1.5 ) * 0.16 = 0.36 Watt
always if I'm not wrong.
I saw that they are added 2 0.1u capacitors between the inverting pin and ground and the non-inverting pin and ground, what are they for?1 October 2019 at 19:52 #6600
Yes, but it should not be on the 5V line?
- You must be logged in to reply to this topic.