Can somebody help me understand the circuit in
The article says that first the capacitor will be charging with an applied negative input voltage. So far so good. When the output reaches a certain voltage the discharge transistor Q1 will turn on and reduce the output voltage.
This is what I don't get. If the voltage is decreasing on the cap after Q1 is turned on, we have now 3 currents at the negative input junction of the OpAmp.
1) Q1 current going upside down 2) Input voltage current going from right to left through the resistors P1,R1 (0 to a negative voltage) 3) Cap discharge current going from left to right (The only way I can think of if the output voltage is decreasing).So now we have at one junction, 3 positive currents going away from the junction, which by KCL is impossible.
So what am I missing ??
Thank you.