1. The problem statement, all variables and given/known data I am trying to figure out how this ckt works. But no idea, where to even begin. see attachment tp.png 2. Relevant equations 3. The attempt at a solution Q1 is diode connected. The Vbe temperature dependence is amplified to indicate the temperature. -2mV/ deg C Gain is about 50. I simplified the ckt to the one in pdf attachment. The -15v is added to inverting terminal and -13.85v is added to non-inverting terminal. Assuming Vbe is 0.64v at room temp, -13.85 and -0.64v add up to -14.5v The difference between invering and non-inverting terminals is 0.5v. Can't go any further.