Your circuit is not acting like a peak detector because the transistor is not working. Your 'scope shows that the output of the opamp correctly shows a fast rise but not high enough (It should rise +0.7V higher than the input signal peak) to turn on the base-emitter of the transistor).
Then the transistor is supposed to very quickly charge the output capacitor but yours is very slow, just like the input signal.
I suspect that the value of R12 is much higher than 100 ohms, maybe it is wrong at 100k ohms? Maybe the opamp and transistor are not powered?
The opamp output high duration is not long enough.
Then the transistor is supposed to very quickly charge the output capacitor but yours is very slow, just like the input signal.
I suspect that the value of R12 is much higher than 100 ohms, maybe it is wrong at 100k ohms? Maybe the opamp and transistor are not powered?
The opamp output high duration is not long enough.