The **HAS-A5-R/Q** refers to a high-precision, open-loop Hall Effect current sensor manufactured by **LEM**. It is designed for electronic measurement of DC, AC, and pulsed currents with galvanic isolation between the primary (high power) and secondary (electronic) circuits. --- ## 1. Technical Specifications The "A5" designation typically indicates a 5V power supply requirement, while "R/Q" denotes specific packaging or pin configurations for PCB mounting. | Parameter | Value / Description | | :--- | :--- | | **Primary Nominal Current ($I_{pn}$)** | 5 A | | **Measuring Range** | ± 15 A (at 5V) | | **Supply Voltage ($V_c$)** | +5 VDC (± 5%) | | **Output Voltage ($V_{out}$)** | 2.5 V ± (0.625 × $I / I_{pn}$) | | **Accuracy** | ± 1% of $I_{pn}$ | | **Linearity** | < ± 0.5% | | **Frequency Bandwidth** | DC to 50 kHz | --- ## 2. Internal Electronic Architecture The device functions based on the **Hall Effect** principle. Below are the key electronic components integrated within the module: ### A. Magnetic Core A ring-shaped magnetic core captures the magnetic flux generated by the primary conductor passing through the center of the sensor. ### B. Hall Generator A thin semiconductor slice (the Hall element) is placed in the gap of the magnetic core. When current flows through the primary wire, the resulting magnetic field creates a "Hall Voltage" across this semiconductor. ### C. Signal Conditioning Circuitry * **Amplifier:** The raw Hall voltage is extremely small (millivolts). An internal operational amplifier scales this to a usable level. * **Reference Voltage ($V_{ref}$):** Since it is a unipolar 5V device, the output is "ratiometric." At zero current, the output is typically $V_{cc}/2$ (2.5V). * **Temperature Compensation:** Internal resistors adjust for thermal drift to ensure accuracy across the operating range (-40°C to +105°C). --- ## 3. Pinout Configuration The sensor usually features 4 or 5 pins for PCB integration: | Pin | Function | Description | | :--- | :--- | :--- | | **+Vcc** | Supply | Positive power supply (+5V) | | **0V** | Ground | Power supply return | | **Vout** | Output | Analog voltage proportional to current | | **Ref** | Reference | Internal reference voltage (optional) | --- ## 4. Typical Application Circuit When integrating this part into an electronic system, it is usually connected to a Microcontroller's Analog-to-Digital Converter (ADC). ```cpp // Logic for Reading HAS-A5-R/Q with a 10-bit ADC float sensorValue = analogRead(A0); float voltage = (sensorValue / 1023.0) * 5.0; // 2.5V is zero current; 0.625V per 5 Amps float current = (voltage - 2.5) / (0.625 / 5.0); ``` ---