CT131 5A/2.5mA Precision Miniature Current Transformer

CT131 5A/2.5mA Precision Miniature Current Transformer is a high-accuracy, PCB-mounted sensing component designed to monitor AC currents with exceptional linearity and safety. This miniature device provides vital galvanic isolation between the primary high-current conductor and your secondary monitoring electronics, ensuring the protection of sensitive microcontrollers. Furthermore, the CT131 transforms a primary input current of up to 5A into a manageable 2.5mA secondary output, allowing for precise measurement via a simple burden resistor. Consequently, engineers often select this model for space-constrained power monitoring applications where reliability is paramount. Therefore, you should integrate this precision transformer into your next energy metering project to achieve professional-grade current sensing.

Key Features:

• High Precision: This transformer offers excellent linearity across its rated range, ensuring your digital readouts remain accurate even during slight current fluctuations.
• Compact Form Factor: The miniature, fully encapsulated housing allows for high-density PCB placement without consuming excessive board real estate.
• Built-in Safety: It provides high dielectric strength and electrical isolation, which effectively shields your control circuitry from hazardous AC line voltages.
• Epoxy Encapsulated: The rugged epoxy coating protects the internal windings from moisture, dust, and mechanical vibration, extending the component’s lifespan.
• Simple Integration: Through-hole pins facilitate easy soldering, however, you must ensure proper burden resistor selection to maintain the desired output voltage scaling.

Technical Specifications:

• Rated Input Current (I_n): 5 A AC
• Rated Output Current (I_out): 2.5 mA AC
• Turns Ratio: 2000:1
• Accuracy Class: ≤ 0.2 Grade
• Linearity Range: 0 to 10 A (at 50 Ω burden)
• Phase Error: ≤ 15′ (at rated input)
• Isolation Voltage: ≥ 2500 V_RMS
• Operating Frequency: 50 Hz to 60 Hz

Mechanical Specifications:

• Housing Material: PBT Flame Retardant Plastic (UL94-V0)
• Internal Filling: Epoxy Resin Encapsulation
• Mounting Type: PCB Through-Hole
• Lead Style: Rigid Tinned Copper Pins

Dimensions:

• Body Height: ≈ 19.0 mm
• Body Width: ≈ 17.5 mm
• Body Depth: ≈ 10.5 mm
• Pin Pitch: ≈ 15.0 mm
• Pin Diameter: ≈ 0.8 mm

Pinout and Wiring:

• Input Side: The primary conductor (carrying the 5A load) usually passes through the center hole of the transformer or connects via designated primary pins depending on the specific PCB footprint.
• Secondary Pin 1 (S1): Connects to one side of the burden resistor and the ADC input of your microcontroller.
• Secondary Pin 2 (S2): Connects to the other side of the burden resistor and the common ground (GND) of your circuit.
• Wiring Note: Moreover, never leave the secondary circuit open while the primary current is flowing, as this can generate dangerously high voltages across the secondary terminals.

Datasheet Reference:

• Download Precision Current Transformer Datasheet

Commonly Used in:

• Digital Power Meters: Providing the primary analog input for calculating real-time energy consumption (kWh).
• Smart Plugs: Measuring the current draw of individual household appliances for home automation data logging.
• Circuit Protection: Serving as the sensing element for over-current protection relays and safety disconnects.

Applications:

• AC Load Monitoring: Tracking the performance of AC motors and industrial machinery to detect potential failures.
• Renewable Energy Systems: Monitoring the output of grid-tied inverters in solar or wind power setups.
• UPS Systems: Measuring current flow in uninterruptible power supplies to manage battery charging and load distribution.

Equivalent Models:

• ZMCT103C: A popular alternative with a similar 5A/5mA or 5A/2.5mA ratio, however, verify the pin spacing before replacement.
• DL-CT08CL5: A functionally equivalent precision miniature current transformer often used in similar power monitoring modules.
• ZMCT118: A high-precision variant that provides a similar current ratio but in a slightly different package size.

Package Includes:

• 1 x CT131 5A/2.5mA Precision Miniature Current Transformer