Conventional sound level meters generally use precision ceramic microphones and discrete solid state circuitry. This report describes a design using an electret microphone and integrated circuit operational amplifiers. The advantages of this design are low cost, ease of manufacture, stable gain, and low power consumption. Construction details are included to permit local manufacture. The complete instrument is capable of meeting the Type 2, General Purpose Sound Level Meter, requirements of ANSI S1.4-1971, American National Standard Specification for Sound Level Meters. (Author).

EPA-550/9-74-0008. AD783808.