Description
The MAX471 GY-471 Current Sensor Module is a compact, high-side DC current and voltage detection board built around the Maxim MAX471 precision current-sense amplifier. It is designed for battery monitoring, portable power systems, solar diagnostics, and general electronics projects where simultaneous current and voltage measurement is required. The module integrates a precision 35 mΩ internal sense resistor, enabling bidirectional current measurement up to ±3A without external shunts . A resistive divider on the voltage detection path scales the input by a factor of 5, allowing safe measurement of DC voltages up to 25V when used with a 5V microcontroller (or up to 16.5V with a 3.3V system) . The board provides separate analog outputs for current (AT) and voltage (VT), which connect directly to the ADC pins of an Arduino, ESP32, or similar controller. Some board variants (typically the purple version) also include a SIGN output for detecting current flow direction, useful for charge/discharge monitoring in battery applications . The MAX471 is an older IC that is no longer officially supported by the manufacturer, but modules remain widely available and are well-suited for educational use, prototyping, and light commercial applications .
Features
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Simultaneous Voltage & Current Sensing: Separate AT (current) and VT (voltage) analog outputs allow real-time power calculation without additional sensors .
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High-Side Current Sensing: Monitors the positive power line without breaking the ground path, preserving ground continuity for the load and MCU .
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Bidirectional Measurement: Measures both source-to-load and load-to-source currents across a ±3A range .
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Precision Internal Sense Resistor: Integrated 35 mΩ resistor with 2% accuracy over temperature eliminates external shunt wiring .
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Onboard Voltage Divider: Scales input voltage by 1/5, enabling safe ADC connection for voltages up to 25V (5V MCU) or 16.5V (3.3V MCU) .
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SIGN Output (Select Variants): Purple board versions include an open-collector SIGN pin indicating current direction (charge vs. discharge) .
Technical Specifications
| Parameter | Specification |
|---|---|
| Sensor IC | MAX471 |
| Supply Voltage | 3V to 36V DC |
| Current Range | ±3A (bidirectional) |
| Voltage Range | 3–25V (5V MCU); 3–16.5V (3.3V MCU) |
| Internal Sense Resistor | 35 mΩ (typical) |
| Accuracy | ±2% over temperature |
| Voltage Divider Ratio | 1/5 (VT output = VIN / 5) |
| Quiescent Current | <100 µA (typical) |
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