[sdiy] OpAmp Output Current Question

[Czech Martin]

Feeding large currents with an op amp can cause
trouble on the supply, the more the higher the frequency.
That way you test your PSRR of the rest of the circuit,
but I do not know if this intended.

A better idea would be to use a noisy supply for those
currents, and let the op amp just control it.
The classical one transistor current source circuit.
It is also linear, since the current is measured as resistor
voltage drop. Since the gain arround the op amp is slightly
lower then 1 there is no stability problem.

Your circuit uses the transistor as current gain element.
Additional gain.
Could give stability trouble, depending on bias point.

m.c.