This sound frequency meter circuit is simple to build and can be constructed in a portable format. In can measure frequencies with a minimum level of 10 mVrms and a maximum frequency of up to 100kHz.

The device is a simple, small, and cheap frequency meter with out any hard to find components to be able to measure frequencies up to 40 MHz while having below 1% errors. Most of the analog and ...

With loudspeakers, an important parameter is the frequency at which their cones resonate. This clever Arduino-based tester ...