Industrial noise hazard meter

Claim 1

A PORTABLE BATTERY POWERED NOISE HAZARD METER ADAPTED TO BE CARRIED AND OPERATED BY ONE HAND AND COMPRISING A CASING OF A SIZE TO PERMIT READY CARRYING BY ONE HAND OF AN OPERATOR, A MICROPHONE FREQUENCY WEIGHTED TO HAVE A RELATIVELY FLAT RESPONSE TO APPROXIMATELY 1000 C.P.S. AND A RISING RESPONSE TO APPROXIMATELY 5000 C.P.S. MOUNTED UPON ONE END OF THE CASING TO BE DIRECTED AT A NOISE SOURCE, AN ADJUSTABLE ATTENUATOR CIRCUIT ELECTRICALLY CONNECTED WITH SAID FREQUENCY WEIGHTED MICROPHONE WITHIN SAID CASING, A SINGLE MOVABLE ADJUSTING ELEMENT FOR THE ATTENUATOR CIRCUIT MOUNTED UPON ONE SIDE OF THE CASING NEAR AND INWARDLY OF SAID MICROPHONE AND ADAPTED TO BE MANIPULATED BY THE THUMB OF THE HAND CARRYING SAID CASING, A POWER SWITCH MOUNTED UPON THE OTHER SIDE OF SAID CASING NEAR THE LONGITUDINAL CENTER OF THE CASING TO BE OPERATED BY ONE FINGER OF THE HAND CARRYING SAID CASING, A TRANSISTOR AMPLIFIER CIRCUIT WITHIN SAID CASING ELECTRICALLY CONNECTED WITH THE OPPOSITE END OF THE ATTENUATOR CIRCUIT AND WITH SAID POWER SWITCH, A BATTERY WITHIN SAID CASING TO ENERGIZE SAID CIRCUITS WHEN THE POWER SWITCH IS HELD CLOSED, A METER DISPOSED WITHIN SAID CASING NEAR THE END THEREOF REMOTE FROM THE MICROPHONE AND HAVING A DIAL VISIBLE ON THE FACE OF THE CASING AND ELECTRICALLY CONNECTED WITH THE OUTPUT OF THE AMPLIFIER CIRCUIT, AND A MOVABLE CALIBRATED DIAL VISIBLE THROUGH A DIAL OPENING IN THE FACE OF THE CASING INTERMEDIATE THE MICROPHONE AND METER DIAL AND NEAR MOVABLE ADJUSTMENT ELEMENT AND OPERATED BY THE LATTER, THE VISIBLE INDICIA ON SAID DIALS BEING DIRECTLY INDICATIVE OF NOISE HAZARD TO HUMAN HEARING.