... The hazardous location of explosive gas mixture , Zone1, Zone 21.2 explosive gas mixture , 1A 2B IIC* 1.3 temperature ... Hz2.6 output sound signal ,1.5V / 300Ω2.7 loop circuit impedance ,1KΩ2.8 distortion factor ,≤2%2.9 Output power amplification ... and electrical properties.3.2 Using the integrated design concept with basic conversations, Noise resection, power amplifier, power circuit and protecting ...