Decibel Sound Pressure Level Meter Circuit This is a design for decibel meter circuit. This circuit is used to measure sound pressure level (SPL) from about 60 to 70 dB. In this circuit, the transistor stage and one LM324 op-amp section are used to amplify the sound that is picked up by an 8 ohm speaker. As voltage comparators, the circuit uses The remaining 3 sections of the LM324 quad op-amp. 3 indicator LEDs are driven by the LM324. This is the figure of the circuit; This circuit uses 3 LEDs as indicators. Each LED represents about a 3dB change in sound level, so that when all 3 LEDs are on, the sound level is about 4 times greater than the level needed to light one LED. the 500K pot can be used to adjust the sensitivity of the circuit. One LED is used as a reference sound level. The other two LEDs is used to indicate about a 2X and 4X increase in volume

Decibel Sound Pressure Level Meter Circuit

This is a design for decibel meter circuit. This circuit is used to measure sound pressure level (SPL) from about 60 to 70 dB. In this circuit, the transistor stage and one LM324 op-amp section are used to amplify the sound that is picked up by an 8 ohm speaker. As voltage comparators, the circuit uses The remaining 3 sections of the LM324 quad op-amp. 3 indicator LEDs are driven by the LM324. This is the figure of the circuit;


This circuit uses 3 LEDs as indicators. Each LED represents about a 3dB change in sound level, so that when all 3 LEDs are on, the sound level is about 4 times greater than the level needed to light one LED. the 500K pot can be used to adjust the sensitivity of the circuit. One LED is used as a reference sound level. The other two LEDs is used to indicate about a 2X and 4X increase in volume