ZMPT112 2mA/2mA Precision Miniature Current Transformer is a highly accurate, PCB-mounted voltage sensing component designed for precision measurement and monitoring of AC mains. This module utilizes a high-quality permalloy core to achieve exceptional linear conversion between input and output currents. Consequently, it provides a safe and effective way to sample high-voltage AC signals by transforming them into low-current levels suitable for microcontroller ADCs. Furthermore, the encapsulated design offers superior insulation and moisture resistance for long-term reliability in industrial environments. Therefore, you can implement the ZMPT112 in smart meters and power quality analyzers to ensure precise voltage tracking with minimal phase error.

Key Features:

High Precision: The transformer delivers an accurate 1:1 current ratio with a typical linear error of less than 0.2%, ensuring high-fidelity signal reproduction.
Compact Form Factor: Its miniature PCB-mount design allows for easy integration into space-constrained power monitoring equipment.
Superior Isolation: The epoxy-encapsulated body provides a high dielectric strength, protecting low-voltage control circuitry from high-voltage AC spikes.
Low Phase Error: This component maintains a phase shift of less than 20 minutes (at 2mA), which is critical for accurate power factor calculations.
Permalloy Core: The use of high-permeability magnetic material ensures a stable response across a wide dynamic range.

Technical Specifications:

Rated Input Current: 2 mA
Rated Output Current: 2 mA
Turns Ratio: 1000:1000
Linearity Range: 0 to 10 mA (0 to 1000 V with external resistor)
Phase Angle Error: ≤ 20′ (Input 2mA, sampling resistor 100 Ω)
Isolation Voltage: 3000 V minimum
Operating Frequency: 50 Hz to 60 Hz
Secondary Resistance: ≈ 80 Ω to 110 Ω
Operating Temperature: −40°C to +70°C

Mechanical Specifications:

Encapsulation: Flame retardant epoxy resin (UL94-V0)
Installation: PCB Through-hole mounting
Pin Material: Tin-plated copper alloy
Environmental Protection: Excellent resistance to vibration and moisture.

Dimensions:

Body Length: ≈ 19.4 mm
Body Width: ≈ 17.2 mm
Body Height: ≈ 18.5 mm
Pin Length: ≈ 3.0 mm
Weight: ≈ 12 g

Pinout and Wiring:

Pin 1 & Pin 2 (Primary): Connect these pins to the AC voltage source through a high-wattage current-limiting resistor to scale the input to 2mA.
Pin 3 & Pin 4 (Secondary): These pins provide the isolated 2mA output current; connect a sampling resistor across them to convert the current into a measurable voltage.
Wiring Note: However, you must ensure the primary resistor is rated for the appropriate voltage and power to prevent overheating during continuous operation.

Datasheet Reference:

Download ZMPT112 Precision Current Transformer Datasheet

Commonly Used in:

Digital Energy Meters: Measuring active and reactive power consumption in residential and commercial units.
Power Quality Analyzers: Detecting voltage sags, swells, and harmonic distortions in AC lines.
Embedded Voltage Sensors: Interfacing mains electricity with low-voltage microcontroller platforms like ESP32 or STM32.

Applications:

AC Voltage Measurement: Safely sampling high-voltage AC waveforms for digital conversion.
Overvoltage Protection: Monitoring line voltage to trigger safety disconnects in power management systems.
Smart Home Devices: Providing energy usage feedback in smart plugs and connected appliances.

Equivalent Models:

ZMPT101B: A common alternative, however, it often comes pre-mounted on a module with an onboard operational amplifier.
ZMPT107: A similar precision voltage transformer with different physical dimensions but comparable current handling.
SCT-013 Series: While typically used for current sensing, some variants serve similar isolation roles in power monitoring setups.