I have these relatively simple circuits of which I need to find the transfer functions. Both circuits involve the use of an OpAmp and a diode after the output of the OpAmp. As an input I have a regular sine wave.
Finding the input/output characteristics of a simple inverting amplifier or passive filter is easy, but I get stuck when trying to find the transfer functions for these circuits:
simulate this circuit– Schematic created using CircuitLab
- The first circuit (with output \$V_{out1}\$) is a peak detector circuit. The capacitor holds the output voltage, while the resistor is there for slowly discharging the capacitor.
- The second circuit (with output \$V_{out2}\$) is a 0 Volt comparator for turning the sine wave into a square wave. I put a diode after the output to only allow positive voltages. The resistor to ground is to reduce the output voltage.
My question is: How can I find the input/output characteristics of these circuits (\$V_{out1} = ... * V_{in}\$ and \$V_{out2} = ... * V_{in}\$)?