Here's an ultrasonic circuit I adapted from others on the Web. It works differently to what you propose, there are two stages of amplification which then dives a schmitt trigger to get 0 or 5v on the output.

Hello Sirch,

Searching for a 40hz piezo amplifier, i found this schematic, but I could not find any info on this circuit.

I would like to construct analog circuitry to measure the pulses emanated from an hc-sr04 - is this centered around 40khz?

Best regards,
C.


Moderator's Note:
Please don't hijack other member's thread, now you have your own.
This thread was split from --
Ultrasonic amplifier/filter problem
https://forum.allaboutcircuits.com/threads/ultrasonic-amplifier-filter-problem.92109/#post-1113822

 

The HC-SR04 uses 40kHz to sense the distance but its output is a pulse width representing the distance (not 40kHz).