Product Description:

YJJ MP702 0-100PPM Planar Semiconductor Ammonia (NH3) Gas Sensor

Features:

MP-702 planar semiconductor ammonia (NH3) gas sensor, with metal packaging, is suitable for detecting ammonia concentrations ranging from 0 to 100 ppm. Its typical applications include ammonia leakage monitoring in refrigerators and cold storages, as well as risk control in aquaculture.

Parameters Sign / Unit Value / Condition Remarks

Detected gas — Air ammonia (NH3) —

Detection range ppm 0 - 100 ppm —

Loop voltage VC ≤ 24 V DC —

Heating voltage VH 5.0 V ± 0.1 V AC/DC —

Load resistance RL Adjustable —

Heating resistance RH 95 Ω ± 10 Ω (at room temperature) —

Heating power consumption PH ≤ 300 mW —

Sensitivity S ≥ 5 (at 50 ppm NH3) S = Rs (air) / Rs (50 ppm NH3)

Concentration slope α ≤ 0.6 α = R100 ppm / R30 ppm NH3

Sensitive body resistance Rs 1 kΩ - 30 kΩ (at 50 ppm NH3) —

Standard test conditions — 20 ℃ ± 2 ℃; 65% ± 5% RH; VC = 5.0 V ± 0.1 V; VH = 5.0 V ± 0.1 V —

Preheating time — ≥ 48 h —

Form / Packaging — Metal packaging, 4 pins 1, 2 pins for heating; 3, 4 pins for measurement

Typical characteristics and usage tips

Working principle: Metal oxide semiconductor gas-sensitive layer, conductivity increases with NH3 concentration, and Rs changes are converted into voltage output through RL.

Response and recovery: Highly sensitive to ammonia, response/recovery is fast, suitable for real-time monitoring.

Environmental impact: Sensitivity is affected by temperature and humidity. Standard test conditions are 20 ℃ / 65% RH; calibration and use should be performed under similar temperature and humidity.

Installation and soldering: Prefer manual soldering; 250 ℃ ≤ 3 s; use the least chlorine-containing rosin flux; avoid volatile silicon substances, corrosive gases, and strong shock and vibration.

Circuit connection and selection tips

Dual voltage supply: VC is the measurement circuit voltage (≤ 24 V DC), VH is the heating voltage (5.0 V AC/DC); connect 1, 2 pins for heating, 3, 4 pins for measurement, they can share the power supply, pay attention to polarity.

RL selection: Convert Rs changes into VRL through RL; RL can be optimized according to the target output range and noise requirements (commonly in the kΩ range).

Long-term storage and aging: Unpowered long-term storage will drift, before use, it is necessary to fully age (1 - 6 months ≥ 72 h; > 6 months ≥ 168 h).

Specifications: