This sound level meter circuit can be used to control the intensity of a sound recording or in a disco. It has 5 measurement domains between 70 and 120 dB; reading accuracy is 0.5 dB. Microphone M1 is ...

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.

Digital multimeters are precise and accurate instruments, with some models being very expensive. No matter the cost, one problem pervades every one of these devices: They do a poor job of conveying ...