Sorry Skogsgurra but I have to go by what the vendor tells me even though I know it will work. I can be liable if something goes wrong and I haven't followed the vendor's specs.
I'm at home so I don't have the documentation to know what the original 3 terminal regulator was. I sent the scope images to the relay vendor and they were the ones that said the current has to be limited to no more then 5 amps even though the spike is of short duration.
The OP184 cured the problem but now I have a problem of a voltage and current spike before the regulator can take affect. I have posted the circuit on my website and the scope pictures are in the photo page of the site. Even if I remove the 1uF cap I still get a current spike above the 5A rating...
BrianG, You are correct about the CMVR. I found that problem on Tuesday and have ordered a OP184 which can handle the rail voltage on the inputs. I'm going to put a zener on the output to avoid having the gate voltage go too high. I could have changed the value of R3 to drop the voltage down but...
Using pin 4 (-Vin and source of the FET) as the reference point the output pin 6 is always above 4V when I believe it should be less then 2.5V (according to the IRL540S data sheet for Gate to Source voltage vs Drain current). It is driving on the FET more then it should be thereby allowing more...
The CA3140 is supposed to work with a supply voltage of 4 to 36V. I am measuring 4.75V between pins 4 and 7. This is the reason the op amp was changed from a HA2640 which could only operate down to 10V between pins 4 and 7. I've checked the FET numerous times and have made the circuit on a...
I have a current limiting circuit posted here-http://home.comcast.net/~catnipone/wsb/html/view.cgi-home.html-.html
It has an input voltage between 14 and 30VDC and is supposed to limit the current to 4 amps. Connected to the inverting input is a 200 ohm resistor and a 1 mA current regulating...
