The Microphone, order code MCA-BTA, $44 and the Microphone channel on the Go Direct® Sound Sensor, order code GDX-SND, $89 are uncalibrated, which means that y axis on microphone waveform graphs has arbitrary units. What you see graphed is the voltage from the microphone. That depends on the sensitivity of the microphone (which varies somewhat with frequency), and the gain of the amplifier (which varies somewhat with frequency).
If we were to calibrate the microphone, the units would be those of pressure, such as kPa.
You cannot use the Microphone (Microphone, order code MCA-BTA, $44) to measure loudness in dB, use the Sound Level Meter, order code SLM-BTA, Sound Level Sensor, order code SLS-BTA, $69, or Sound Level channels on the Go Direct® Sound Sensor, order code GDX-SND, $89 instead.