Check the listing for details. BD135 (4 pcs) TO-126 PNP Triode Transistor - Free shipping. Condition: New. Listed at 4.95 USD. Shipping Option 1. Standard shipping(Free): USPS First Class Standard mail -. Small Envelope Mail for small items Without Tracking. (Est. delivery: 4 - 5 business days) -. Non-Machinable Bubble Envelope Mail with IMB Code but Without Tracking. (Est. delivery: 4 - 8 business days) ** Any order from outside U.S. must choose a shipping option #2 or #3 below for their order to be delivered . ** ** Cualquier pedido desde fuera de EE. UU. debe elegir una opción de envío n.° 2 o n.° 3 a continuación para que se entregue su pedido. ** 2. Optional Ebay discount shipping #2 ($5.95): USPS ground advantage (*** small bubble envelope ***) With Tracking. (Est. delivery: 2 - 5 business days) 3. Optional Ebay discount shipping #3 ($10.45): USPS Priority Mail Small Flat Rate Box With Tracking.(Est. delivery: 2 - 3 business days) *** No international shipping either directly or indirectly with the Standard shipping above *** *** No se realizan envíos internacionales ni directa ni indirectamente con el envío estándar anterior *** =============================================================================== The BD135 and BD136 are NPN and PNP power transistors, respectively, commonly used in switching and amplification applications, particularly in higher power circuits. These transistors are typically used in audio amplification, power control, and other applications that require the handling of relatively high currents and voltages.BD135: NPN Power TransistorBD136: PNP Power Transistor Both of these transistors are complementary pairs, meaning they are designed to work together in push-pull configurations in various amplifier and switching circuits.Key Features:Type:BD135: NPN power transistorBD136: PNP power transistorCollector-Emitter Voltage (Vce): 80V (maximum)Collector Current (Ic): 1.5A (maximum)Power Dissipation: 12W (maximum)Current Gain (hFE): Typically 40 to 320, depending on the specific model.How They Work: Complementary Push-Pull Amplification:The BD135 (NPN) and BD136 (PNP) are often used together in push-pull amplifier circuits, especially in audio amplifiers. In such circuits, the NPN transistor handles the positive part of the signal, while the PNP transistor handles the negative part. This configuration helps to efficiently amplify both halves of an AC signal, improving the overall performance and reducing distortion.The BD135 is used for the positive portion of the waveform, and the BD136 handles the negative portion. They work together to push and pull current through the load (e.g., speakers or motors), effectively amplifying the input signal. Switching Applications:Both transistors can be used individually as switches. When used as a switch, a small current applied to the base controls the much larger current flowing between the collector and emitter. For instance, they can be used in circuits to control larger loads, such as motors or relays, from low-power control signals.BD135 (NPN) typically turns on when a positive current is applied to the base relative to the emitter, allowing current to flow from the collector to the emitter.BD136 (PNP) turns on when a negative current is applied to the base relative to the emitter, allowing current to flow from the emitter to the collector. Power Amplifiers:In audio amplifiers, the BD135 and BD136 can be used to drive speakers or other high-power components. These transistors amplify the input audio signal and can deliver higher current to power speakers.Pin Configuration: BD135 (NPN):Collector (C): The output terminal, typically connected to the load.Base (B): The input terminal, where a small current controls the operation of the transistor.Emitter (E): The reference terminal, usually connected to ground or a lower voltage source. BD136 (PNP):Collector (C): The output terminal, typically connected to the load.Base (B): The input terminal, where a small current controls the operation of the transistor.Emitter (E): The reference terminal, usually connected to a higher voltage source.Example Circuits: Push-Pull Amplifier:In a push-pull amplifier, the BD135 and BD136 are used together to amplify both positive and negative portions of an AC signal. The BD135 amplifies the positive part, and the BD136 amplifies the negative part, creating a more efficient and less distorted amplification process.The base of each transistor receives the appropriate signal (positive for NPN, negative for PNP), which causes them to alternate between conducting and non-conducting states. Switching a Motor:BD135 (NPN) and BD136 (PNP) can also be used to control a motor in a H-bridge configuration. The NPN transistor is used to allow current to flow through the motor in one direction, while the PNP transistor allows current to flow in the opposite direction when the control signal changes.Key Notes:BD135 and BD136 are often used together in complementary push-pull amplifier configurations to handle higher power, making them ideal for audio applications, motor drivers, and other power control circuits.They are designed to handle relatively high currents (up to 1.5A) and voltage (up to 80V), which makes them suitable for driving higher power loads.Base current limiting resistors are recommended to prevent excess current from flowing into the base and damaging the transistor.