The **E-41PD-R** is an infrared (IR) photodiode specifically designed for high-speed detection and optical communication. Below is a detailed breakdown of its electronic specifications and characteristics. --- ### 1. General Overview The E-41PD-R is a **Silicon PIN Photodiode** housed in a radial leaded package (usually a 5mm / T1-3/4 standard size). It is optimized for detecting near-infrared light and converting it into electrical current. ### 2. Technical Specifications | Parameter | Description | Typical Value | | :--- | :--- | :--- | | **Material** | Semiconductor Base | Silicon (Si) | | **Peak Sensitivity Wavelength** | $\lambda_p$ | 940 nm | | **Spectral Range** | Detection Bandwidth | 400 nm – 1100 nm | | **Open Circuit Voltage** | $V_{oc}$ | 0.39 V | | **Short Circuit Current** | $I_{sc}$ | 35 $\mu$A (at 1mW/cm²) | | **Reverse Breakdown Voltage** | $B_{vr}$ | 32 V | | **Response Time** | Rise/Fall Time ($t_r/t_f$) | 45 ns / 45 ns | | **Total Capacitance** | $C_t$ | 25 pF (at $V_r = 3V$) | --- ### 3. Key Electronic Characteristics * **PIN Structure:** Unlike standard PN diodes, the PIN structure (P-layer, Intrinsic layer, N-layer) allows for a wider depletion region. This results in lower capacitance and significantly faster switching speeds, making it ideal for data transmission. * **Visible Light Filter:** The "R" in the suffix often denotes a **Daylight Filter**. The resin mold is usually black or dark blue to block visible light interference and only allow infrared light to reach the chip. * **Linearity:** The output current is highly linear relative to the incident light intensity, which simplifies the design of light-measuring circuits. --- ### 4. Circuit Implementation To use the E-41PD-R effectively, it is typically used in one of two modes: 1. **Photovoltaic Mode:** The diode is used without a bias voltage. It generates a small voltage when illuminated. Used for low-speed, low-noise applications. 2. **Photoconductive Mode:** The diode is **Reverse Biased** (e.g., connected to a 5V source in reverse). This decreases response time and increases sensitivity, making it suitable for high-speed pulse detection. #### Basic Connection Diagram ```text [ VCC (+5V) ] | [ Resistor R1 ] <-- Current Limiting / Signal Output | +----[ Output Vout ] | _|_ (Cathode) \ / E-41PD-R (Reverse Biased) --- (Anode) | [ GND ] ``` --- ### 5. Common Applications * **Infrared Remote Controls:** TV, Air Conditioner, and Stereo receivers. * **Optical Switch:** Counting objects on a conveyor belt or detecting door positions. * **Encoders:** Measuring motor RPM via an IR slotted disc. * **Light Curtains:** Safety barriers in industrial machinery.