Hello all,
I saw an application note on RTD circuits at http://www.eetasia.com/ARTICLES/2007AUG/PDF/EEOL_2007AUG01_INTD_AN.pdf?SOURCES=DOWNLOAD, and I'm wondering why their current source circuit uses two op-amps instead of the simple one op-amp current source like the one here: http://www.ecircuitcenter.com/Circuits/curr_src1/curr_src1.htm. As far as I can tell, for the simple one, you don't even need the transistor if you only need low currents.
What's the advantage of the first circuit?
I saw an application note on RTD circuits at http://www.eetasia.com/ARTICLES/2007AUG/PDF/EEOL_2007AUG01_INTD_AN.pdf?SOURCES=DOWNLOAD, and I'm wondering why their current source circuit uses two op-amps instead of the simple one op-amp current source like the one here: http://www.ecircuitcenter.com/Circuits/curr_src1/curr_src1.htm. As far as I can tell, for the simple one, you don't even need the transistor if you only need low currents.
What's the advantage of the first circuit?