I am using channel 2 of TL103WA as a unity gain buffer (non-inverting). Vcc is 5V, Vee is gnd.
The input is 0.45V. The output of the buffer is connected to junction of an 8.5K resistor and a 1k resistor. See attachment.
The opamp is sinking current of about 50uA. The intersection of 8.5k and 1k form a resistor divider. The voltage at the intersection is 0.5V.
I tried to calculate the output impedance of the opamp. (0.45-0.5)/50uA = 1Kohms !!??
I don't get it. Opamps usually have output impedance in the range of 100-200 ohms. Whats wrong here?