## Overview of the 2SC1923-R Transistor The **2SC1923-R** is a high-frequency NPN epitaxial silicon transistor designed specifically for low-noise amplifier and oscillator applications. It is commonly found in the RF (Radio Frequency) stages of FM tuners, communication equipment, and TV receivers. --- ### Technical Specifications The "R" suffix typically refers to the **hFE (DC Current Gain)** classification, indicating a specific range of gain performance. | Parameter | Symbol | Rating | Unit | | :--- | :--- | :--- | :--- | | Collector-Base Voltage | $V_{CBO}$ | 40 | V | | Collector-Emitter Voltage | $V_{CEO}$ | 30 | V | | Emitter-Base Voltage | $V_{EBO}$ | 4 | V | | Collector Current | $I_{C}$ | 20 | mA | | Base Current | $I_{B}$ | 4 | mA | | Collector Power Dissipation | $P_{C}$ | 100 | mW | | Junction Temperature | $T_{j}$ | 125 | °C | | Gain Bandwidth Product | $f_{T}$ | 550 (typ) | MHz | --- ### Key Features * **High Transition Frequency ($f_{T}$):** With a typical value of 550 MHz, it is highly effective for VHF/UHF amplification. * **Low Noise Figure:** Specifically engineered to maintain signal integrity in sensitive receiver front-ends. * **Low Capacitance:** Small reverse transfer capacitance ($C_{re}$), which improves stability in high-frequency circuits. * **Classification:** The "R" grade usually indicates a DC current gain ($h_{FE}$) range of approximately **40 to 80**. --- ### Pin Configuration (TO-92 Package) Looking at the flat side of the transistor with the leads pointing down: 1. **Emitter (E):** Provides the carrier flow. 2. **Collector (C):** Collects the carriers. 3. **Base (B):** Controls the transistor gate. ```markdown _______ / \ | 1923-R | |_________| | | | E C B 1 2 3 ``` --- ### Common Applications 1. **FM Radio Tuners:** Used in the RF amplifier stage to boost weak radio signals. 2. **Local Oscillators:** Its high frequency stability makes it ideal for generating carrier waves. 3. **Frequency Mixers:** Used to convert high-frequency signals to intermediate frequencies (IF). 4. **Signal Boosters:** Small-signal amplification for communication devices.