I am trying to convert 5V to a constant current source
for op amp I use AD822. for 250 ohm I use 180 ohm, so I should get a current of 28 mA. I verified when Rload = 0, 28 mA across negative terminal to ground.
But when I put Rload to circuit, 680 ohm, my current exceeds 28mA as Vcc increase.
Can anyone please point where might be the error?