## Overview of the TIP136 Transistor The **TIP136** is a silicon PNP **Darlington Power Transistor**. It is designed for general-purpose amplifier and low-speed switching applications. Because it is a Darlington pair, it offers a very high current gain compared to standard bipolar transistors. --- ### 1. Key Technical Specifications The following table summarizes the absolute maximum ratings and electrical characteristics of the TIP136: | Parameter | Symbol | Maximum Rating | | :--- | :--- | :--- | | Collector-Emitter Voltage | $V_{CEO}$ | -100 V | | Collector-Base Voltage | $V_{CBO}$ | -100 V | | Emitter-Base Voltage | $V_{EBO}$ | -5 V | | Collector Current (Continuous) | $I_C$ | -8 A | | Collector Current (Peak) | $I_{CP}$ | -12 A | | Base Current | $I_B$ | -0.3 A | | Total Power Dissipation ($T_C = 25°C$) | $P_D$ | 70 W | | DC Current Gain ($I_C = -4A, V_{CE} = -4V$) | $h_{FE}$ | 1000 (Min) - 15000 (Max) | --- ### 2. Internal Configuration The TIP136 is not a single transistor but a **Darlington Pair**. This internal structure consists of: * **Two Transistors:** The first transistor amplifies the input signal, which is then further amplified by the second transistor. * **Integrated Resistors:** Built-in base-emitter resistors to help with turn-off time and stability. * **Protection Diode:** An integrated anti-parallel collector-emitter diode to protect the device against reverse current spikes (common in inductive loads). --- ### 3. Pin Configuration (TO-220 Package) When looking at the front of the transistor (metal tab at the back, pins pointing down), the layout is as follows: 1. **Pin 1 (Base):** Controls the biasing of the transistor. 2. **Pin 2 (Collector):** Connected to the load (and the metal mounting tab). 3. **Pin 3 (Emitter):** Connected to the ground or negative rail. --- ### 4. Common Applications Due to its high gain and power handling, the TIP136 is frequently used in: * **Motor Control:** Driving DC motors where high current is required from low-power logic signals. * **Relay Drivers:** Switching high-voltage relays. * **Audio Power Amplifiers:** Used in the output stages of power amps. * **Solenoid Drivers:** Handling the inductive kickback and high current of solenoids. --- ### 5. Complementary Pair The TIP136 (PNP) is often used in conjunction with its **NPN complementary** counterpart, the **TIP131** or **TIP132**, for push-pull amplifier configurations.