The **HAS-55-R** and **HAS-55-Q** are high-performance **Open Loop Hall Effect Current Transducers** manufactured by **LEM**. These components are designed for the electronic measurement of DC, AC, and pulsed currents with galvanic isolation between the primary (high power) and secondary (electronic) circuits. --- ## 1. Technical Specifications The "55" in the part number typically refers to the nominal current rating, while the suffixes (R/Q) often denote specific package styles or pin configurations within the series. | Feature | Specification | | :--- | :--- | | **Primary Nominal Current ($I_{pn}$)** | 50 A (RMS) | | **Measuring Range** | ± 150 A | | **Supply Voltage ($V_c$)** | ± 15 V (± 5%) | | **Output Voltage ($V_{out}$)** | ± 4 V (at $I_{pn}$) | | **Accuracy** | ± 1% of $I_{pn}$ | | **Frequency Bandwidth** | DC to 50 kHz | | **Technology** | Hall Effect (Open Loop) | --- ## 2. Key Electronic Components & Internal Logic The device operates on the principle of the Hall Effect. Below are the internal functional blocks: ### A. Magnetic Core A high-permeability ring or "C" core concentrates the magnetic flux generated by the primary conductor passing through the center aperture. ### B. Hall Generator A thin semiconductor slice placed in the air gap of the magnetic core. When current flows through the primary, the resulting magnetic field induces a **Hall Voltage** ($V_h$) across this semiconductor. ### C. Signal Conditioning Circuit Because the raw Hall voltage is very small (millivolts) and sensitive to temperature, the internal electronics include: * **Differential Amplifier:** Boosts the signal to the standard ± 4V level. * **Temperature Compensation:** Internal resistors/thermistors that offset drift caused by heat. * **Voltage Regulator:** Ensures stable internal operation despite minor fluctuations in the ± 15V supply. --- ## 3. Comparison of Suffixes (R vs. Q) While the core electrical characteristics remain the same, the suffix usually indicates the physical mounting or terminal style: | Suffix | Typical Meaning | | :--- | :--- | | **HAS-55-R** | Often indicates a **Right-angle** or specific lead-form orientation for PCB mounting. | | **HAS-55-Q** | Generally refers to a **Quick-connect** or specific terminal post version for easier wiring. | --- ## 4. Connection Diagram (Standard Pinout) The secondary side typically features four pins: 1. **+VC**: Positive Supply (+15V) 2. **-VC**: Negative Supply (-15V) 3. **Output**: Measurement Signal (0 to ± 4V) 4. **0V**: Common Ground/Return ```text [ Primary Conductor ] | | +-------------------+ | HAS-55 | +-------------------+ | | | | +Vc -Vc Out 0V ``` ---